Inkjet ink, inkjet printing method, and method for producing inkjet ink

Abstract

To provide an inkjet ink that does not cause a structure of an inkjet printer to be used to be complicated as much as possible and allows the printing of images having excellent dispersibility and storage stability, reduced defective images and excellent friction fastness, and can also prevent tactile of the printed matter from deteriorating.SOLUTION: An inkjet ink includes an aqueous medium, composite particles, and a cross-linking agent. The composite particles are emulsified particles of a composite of a polyester resin and a disperse dye. The polyester resin includes a repeating unit derived from a polyhydric alcohol and a repeating unit derived from a polycarboxylic acid. The polyester resin is non-crystalline one. The polyester resin has a glass transition point of at least 45°C and no higher than 75°C. The polyester resin has an acid value of at least 10 mgKOH / g and no greater than 70 mgKOH / g. The polyester resin has a hydroxyl value of at least 20 mgKOH / g and no greater than 60 mgKOH / g. The cross-linking agent includes a block isocyanate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ink-jet ink, an ink-jet printing method, and a method for producing an ink-jet ink. [Background technology]

[0002] Inks for digital textile printing have been studied for printing images on textile products such as cloth using an inkjet textile printing device. For example, the hot melt ink for inkjet printing described in Patent Document 1 is a solid type ink that contains a dye and a water-soluble substance that is solid at room temperature and that holds the dye in the ink. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-265836 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the hot melt ink described in Patent Document 1 is a solid type ink, and therefore needs to be used in a hot melt type inkjet printing device. A hot melt type inkjet printing device is configured to heat hot melt ink, which is solid at room temperature, to liquefy it and eject it from the nozzles of a recording head. This leads to a complex device configuration.

[0005] The present invention has been made in view of the above problems, and its object is to provide an inkjet ink that is excellent in dispersibility and storage stability, can print an image with few image defects and excellent friction fastness without complicating the configuration of the inkjet printing device used, and can suppress deterioration in the tactile feel of the printed object (printed item) on which the image is printed, and a method for producing the same. Another object of the present invention is to provide an inkjet printing method that can suppress aggregation of the inkjet ink by using an inkjet ink that is excellent in dispersibility and storage stability, can print an image with few image defects and excellent friction fastness, and can suppress deterioration in the tactile feel of the printed item, without complicating the configuration of the inkjet printing device used. [Means for solving the problem]

[0006] The inkjet ink according to the present invention contains an aqueous medium, composite particles, and a crosslinking agent. The composite particles are emulsified particles of a composite of a polyester resin and a disperse dye. The polyester resin has a repeating unit derived from a polyhydric alcohol and a repeating unit derived from a polycarboxylic acid. The polyester resin is non-crystalline. The polyester resin has a glass transition point of 45° C. or more and 75° C. or less. The polyester resin has an acid value of 10 mgKOH / g or more and 70 mgKOH / g or less. The polyester resin has a hydroxyl value of 20 mgKOH / g or more and 60 mgKOH / g or less. The crosslinking agent contains a blocked isocyanate.

[0007] The ink-jet printing method according to the present invention includes a step of ejecting ink from a recording head onto an object to be printed. The ink is the ink-jet ink described above.

[0008] The method for producing an inkjet ink according to the present invention includes a kneading step of kneading the polyester resin and the disperse dye to obtain a kneaded mixture, a composite particle formation step of forming the composite particles by phase inversion emulsification of an oil phase containing the kneaded mixture and an organic solvent and an aqueous phase containing water, and a mixing step of mixing the composite particles, the aqueous medium, and the crosslinking agent to obtain an ink. The ink is the inkjet ink already described. Effect of the Invention

[0009] The inkjet ink according to the present invention and the inkjet ink produced by the production method according to the present invention are excellent in dispersibility and storage stability, and can print images with few image defects and excellent friction fastness without complicating the configuration of the inkjet textile printing device used, and can suppress deterioration in the tactile feel of the printed textile. Furthermore, the inkjet textile printing method of the present invention uses an inkjet ink with excellent dispersibility and storage stability, and can suppress aggregation of the inkjet ink without complicating the configuration of the inkjet textile printing device used, and can print images with few image defects and excellent friction fastness, and can suppress deterioration in the tactile feel of the printed textile. [Brief description of the drawings]

[0010] [Figure 1] FIG. 11 is a diagram showing an example of an inkjet textile printing apparatus used in an inkjet textile printing method according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First, the meaning of the terms used in this specification and the measurement method will be explained. The compound and its derivatives may be collectively referred to by adding "system" after the compound name. When the polymer name is expressed by adding "system" after the compound name, it means that the repeating unit of the polymer is derived from the compound or its derivative. The "main component" of a material means the component that is contained most in the material by mass unless otherwise specified. The strength of hydrophobicity (or strength of hydrophilicity) can be expressed, for example, by the contact angle of a water droplet (ease of wetting with water). The larger the contact angle of the water droplet, the stronger the hydrophobicity. Each component described in this specification may be used alone or in combination of two or more unless otherwise specified. The softening point (Tm) is a value measured using a high-temperature flow tester (Shimadzu Corporation "CFT-500D"). Each of the number average molecular weight (Mn) and mass average molecular weight (Mw) is a value measured using gel permeation chromatography unless otherwise specified. Now that the meanings of the terms used in this specification and the measurement methods have been explained, an embodiment of the present invention will be described.

[0012] [First embodiment: Inkjet ink] The first embodiment of the present invention relates to an inkjet ink (hereinafter, referred to as ink). The ink of the first embodiment can be used, for example, to print an image on a printing object using an inkjet printing device. That is, the ink of the first embodiment can be used as an ink for digital printing. Compared with screen printing and rotary screen printing, digital printing has the advantage that a process for removing a paste is not required, and that dyeing wastewater can be reduced. Also, compared with the pre-dyeing method and the dip-dyeing method, which dye a large amount of fibers, digital printing has the advantage that printing can be performed in small lots, and that no waste liquid is generated when changing the dyeing color.

[0013] The ink of the first embodiment contains an aqueous medium, composite particles, and a crosslinking agent. The ink of the first embodiment is an aqueous ink containing an aqueous medium. The ink preferably further contains a neutralizing agent as necessary. The composite particles, the crosslinking agent, the neutralizing agent, and the aqueous medium will be described below.

[0014] <Composite particles> The composite particles are emulsified particles of a composite of a polyester resin and a disperse dye. The composite particles are, for example, dispersed (e.g., emulsified and dispersed) in an aqueous medium. When an ink containing the composite particles lands on an object to be printed (e.g., a textile product such as polyester cloth or cotton cloth), the object to be printed and the composite particles are adhered to each other via the polyester resin in the composite particles. As a result, the abrasion fastness of the printed image is improved.

[0015] In addition, when the ink containing the composite particles is landed on a printing target and heat-treated, the hydroxyl groups of the printing target and the hydroxyl groups of the polyester resin in the composite particles are crosslinked by the crosslinking agent to form a crosslinked structure. In the first embodiment, since the hydroxyl value of the polyester resin in the composite particles is within a predetermined range described later, there are many reactive sites that can react with the crosslinking agent, and the crosslinked structure is sufficiently formed by the crosslinking agent. As a result, the friction fastness of the printed image is particularly improved.

[0016] In addition, when the ink containing the composite particles lands on a printing target and is heat-treated, the composite particles are also plastically deformed on the printing target due to the plastic deformation of the polyester resin. Since the plastically deformed composite particles spread over the surface of the printing target, an image with high image density can be printed even with a small amount of ink. Furthermore, unlike the bleeding of disperse dyes that spreads due to capillary action along the fibers of the printing target, the dyed area spreads due to the plastic deformation of the composite particles, and therefore the image printed using the ink containing the composite particles becomes clear.

[0017] The volume median diameter of the composite particles (hereinafter referred to as D 50The diameter of the composite particles is preferably 20 nm or more and 300 nm or less, more preferably 85 nm or more and 180 nm or less, and even more preferably 100 nm or more and 150 nm or less. 50 When the D of the composite particles is 300 nm or less, the composite particles are suitably emulsified and dispersed in an aqueous medium, and an ink having excellent dispersion stability can be obtained. 50 When the D of the composite particles is 300 nm or less, the composite particles contained in the ink are less likely to aggregate, and clogging of the nozzles of the recording head is suppressed. In addition, the color development of the printed image is improved. 50 can be adjusted, for example, by changing the acid value of the polyester resin contained in the composite particle. The smaller the acid value of the polyester resin, the lower the D 50 In addition, the D of the composite particles tends to be large. 50 can be adjusted, for example, by changing the stirring conditions (more specifically, the stirring speed, stirring time, the presence or absence of a neutralizing agent, etc.) in the composite particle preparation step described below. 50 can be adjusted, for example, by changing the type of aqueous medium. 50 is measured, for example, by the method described in the Examples.

[0018] The content of the composite particles is preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass, relative to the mass of the ink.

[0019] (Polyester resin constituting composite particles) The polyester resin constituting the composite particles is non-crystalline. Here, crystalline polyester resin is difficult to dye with disperse dye. Conversely, non-crystalline polyester resin is easily dyed with disperse dye. The crystalline region of the polyester resin is dense and difficult to soften, but the non-crystalline region softens with increasing temperature, weakening the entanglement of the resin chains, and the disperse dye easily penetrates. The non-crystalline region of the non-crystalline polyester resin is dyed with a disperse dye, and the non-crystalline polyester resin and the disperse dye are well complexed. The non-crystalline nature of the polyester resin can be confirmed, for example, by differential scanning calorimetry (DSC). When the polyester resin has a glass transition point (Tg) but does not have a clear melting point (Mp), the polyester resin is judged to be non-crystalline. When the polyester resin has a glass transition point (Tg) and a melting point (Mp), the polyester resin is judged to be crystalline.

[0020] The glass transition point of the polyester resin is 45°C or more and 75°C or less. When the glass transition point of the polyester resin is 45°C or more, the polyester resin is unlikely to soften in a room temperature environment, and fusion and aggregation of the composite particles in the ink is unlikely to occur. As a result, an ink with excellent storage stability is obtained. On the other hand, when the glass transition point of the polyester resin is 75°C or less, the printed image does not become too hard. As a result, the printed item is unlikely to swell and lose its stiffness, and the deterioration of the tactile feel of the printed item can be suppressed. In addition, when the glass transition point of the polyester resin is 75°C or less, even when the ink containing the composite particles is not heated after landing on the printed item or is heated at a low temperature, the composite particles containing the polyester resin are well adhered to the printed item. As a result, the friction fastness of the printed image is improved. In addition, when the glass transition point of the polyester resin is 45°C or more and 75°C or less, when the ink containing the composite particles lands on the printing object and is heated, the composite particles are suitably plastically deformed on the printing object. Since the plastically deformed composite particles spread over the surface of the printing object, an image with high image density can be printed even when a small amount of ink is used. In order to obtain an ink with excellent storage stability, the glass transition point of the polyester resin is preferably 50°C or more, more preferably 55°C or more. In order to suppress the deterioration of the tactile feel of the printed material, the glass transition point of the polyester resin is preferably 70°C or less, more preferably 60°C or less. The glass transition point of the polyester resin is measured, for example, by the method described in the Examples.

[0021] The acid value of the polyester resin is 10 mgKOH / g or more and 70 mgKOH / g or less. When the acid value of the polyester resin is 10 mgKOH / g or more, the amount of carboxyl groups in the polyester resin is increased, and the polyester resin is given an appropriate polarity. As a result, the composite particles containing the polyester resin are well emulsified and dispersed in the aqueous medium, and an ink with excellent dispersibility is obtained. In addition, the phase inversion emulsification described later in the second embodiment proceeds favorably. In addition, an ink capable of printing an image with few image defects is obtained. On the other hand, when the acid value of the polyester resin is 70 mgKOH / g or less, the amount of hydrophilic carboxyl groups is not too large, and the polyester resin is given an appropriate water resistance. As a result, the wet rub fastness of the printed image is improved. In order to obtain an ink with excellent dispersibility, the acid value of the polyester resin is preferably 20 mgKOH / g or more. In order to improve the wet rub fastness of the printed image, the acid value of the polyester resin is preferably 60 mgKOH / g or less. The acid value of the polyester resin is measured, for example, by the method described in the Examples.

[0022] The hydroxyl value of the polyester resin is 20 mgKOH / g or more and 60 mgKOH / g or less. When the hydroxyl value of the polyester resin is 20 mgKOH / g or more, the amount of hydroxyl groups in the polyester resin increases, and the number of reaction sites that can react with the crosslinking agent increases. Therefore, when the ink containing the composite particles is landed on the object to be printed and heated, a crosslinking structure is sufficiently formed by the crosslinking agent between the hydroxyl groups in the polyester resin in the composite particles and the hydroxyl groups in the object to be printed. As a result, image defects are less likely to occur in the printed image. In addition, when the hydroxyl value of the polyester resin is 20 mgKOH / g or more, the amount of hydroxyl groups in the polyester resin increases, and the polyester resin is given an appropriate polarity. As a result, the composite particles containing the polyester resin are well emulsified and dispersed in the aqueous medium, and an ink with excellent dispersibility is obtained. On the other hand, when the hydroxyl value of the polyester resin is 60 mgKOH / g or less, the amount of hydrophilic hydroxyl groups is not too large, and the polyester resin is given an appropriate water resistance. As a result, the wet rub fastness of the printed image is improved. Furthermore, when the hydroxyl value of the polyester resin is 60 mgKOH / g or less, the amount of hydrophilic hydroxyl groups is not too large, and the printed item is less likely to become slimy. As a result, the deterioration of the tactile feel of the printed item is suppressed. In order to suppress the occurrence of image defects and obtain an ink with excellent dispersibility, the hydroxyl value of the polyester resin is preferably 22 mgKOH / g or more, and more preferably 25 mgKOH / g or more. The hydroxyl value of the polyester resin is measured, for example, by the method described in the Examples.

[0023] The softening point of the polyester resin is preferably 80° C. or higher and 200° C. or lower. When the softening point is 80° C. or higher, an ink with good fixability and storage stability is obtained. In order to ensure good adhesion of the composite particles to the object to be printed, the softening point of the polyester resin is preferably 130° C. or higher and 200° C. or lower.

[0024] The number average molecular weight of the polyester resin is preferably 2500 or more and 30000 or less, more preferably 4000 or more and 30000 or less, and even more preferably 10000 or more and 30000 or less. When the number average molecular weight of the polyester resin is 2500 or more, the strength of the ink film of the printed material is improved. When the number average molecular weight of the polyester resin is 30000 or less, the viscosity of the liquid containing the polyester resin does not become too high during preparation of the composite particles, and the polyester resin and the disperse dye can be uniformly composited.

[0025] The content of polyester resin in the composite particles is preferably 50% by mass or more and less than 100% by mass. Hereinafter, "the content of polyester resin in the composite particles" may be referred to as "polyester resin ratio". When the polyester resin ratio is 50% by mass or more, the amount of polyester resin is large, so that when the ink lands on the object to be printed, the object to be printed and the composite particles are suitably adhered to each other, and the abrasion fastness of the printed image is improved. In order to improve the abrasion fastness of the printed image, the polyester resin ratio is preferably 60% by mass or more, and more preferably 70% by mass or more. In order to print an image having a high image density, the polyester resin ratio is preferably 95% by mass or less, and more preferably 90% by mass or less. The polyester resin ratio can be changed, for example, by changing the amount of polyester resin and the amount of disperse dye added when preparing the composite particles.

[0026] The polyester resin has a repeating unit derived from a polyhydric alcohol and a repeating unit derived from a polycarboxylic acid. The polyester resin is a polymer of at least one polyhydric alcohol and at least one polycarboxylic acid. In the following description, examples of polycarboxylic acids and examples of polyhydric alcohols may be used to describe examples of repeating units derived from polycarboxylic acids and repeating units derived from polyhydric alcohols, respectively. For example, when the polycarboxylic acid monomer is "A", the repeating unit derived from the polycarboxylic acid is a "repeating unit derived from A". For example, when the polyhydric alcohol monomer is "B", the repeating unit derived from the polyhydric alcohol is a "repeating unit derived from B".

[0027] (Repeating units derived from polyhydric alcohol) Examples of the repeating unit derived from a polyhydric alcohol include a repeating unit derived from a dihydric alcohol and a repeating unit (first repeating unit) derived from a trihydric or higher alcohol. As the repeating unit derived from a trihydric or higher alcohol, a repeating unit derived from a trihydric or tetrahydric alcohol is preferable.

[0028] The repeating unit derived from polyhydric alcohol contains at least a first repeating unit derived from a trihydric or higher alcohol, and the content of the first repeating unit in the total amount (total substance amount) of repeating units derived from polyhydric alcohol is preferably 0.5 mol% to 10.0 mol%, more preferably 2.0 mol% to 6.5 mol%. In this case, the repeating unit derived from polyhydric alcohol further contains a repeating unit derived from a dihydric alcohol in addition to the first repeating unit. Hereinafter, the "content of the first repeating unit derived from a trihydric or higher alcohol in the total amount of repeating units derived from polyhydric alcohol" may be referred to as the "trihydric or higher alcohol ratio". When the trihydric or higher alcohol ratio is 0.5 mol% to 10.0 mol%, the hydroxyl value of the polyester resin is suitably adjusted to a value within a predetermined range.

[0029] The repeating unit derived from polyhydric alcohol contains at least a second repeating unit derived from ethylene glycol, and the content of the second repeating unit in the total amount (total substance amount) of the repeating units derived from polyhydric alcohol is preferably 50.0 mol% to 90.0 mol%, more preferably 55.0 mol% to 70.5 mol%, and even more preferably 60.0 mol% to 70.0 mol%. In this case, the repeating unit derived from polyhydric alcohol further contains a repeating unit derived from a polyhydric alcohol other than ethylene glycol in addition to the repeating unit derived from ethylene glycol. Hereinafter, the "content of the second repeating unit derived from ethylene glycol in the total amount of repeating units derived from polyhydric alcohol" may be referred to as the "EG ratio". When the EG ratio is 50.0 mol% to 90.0 mol%, the glass transition point of the polyester resin is suitably adjusted to a value within a predetermined range.

[0030] Since the hydroxyl value of the polyester resin can be easily adjusted to a value within a predetermined range, the polyester resin preferably has repeating units derived from two or more types of polyhydric alcohols, more preferably has repeating units derived from two or more and four or less types of polyhydric alcohols, and even more preferably has repeating units derived from three or four types of polyhydric alcohols.

[0031] Examples of polyhydric alcohols that can be used in the polymerization of polyester resins include aliphatic polyhydric alcohols, alicyclic polyhydric alcohols, aromatic polyhydric alcohols, and other polyhydric alcohols.

[0032] The aliphatic polyhydric alcohol is a dihydric aliphatic alcohol or a trihydric or higher aliphatic alcohol. Examples of the dihydric aliphatic alcohol include dihydric aliphatic alcohols having 2 to 8 carbon atoms (more specifically, ethylene glycol, diethylene glycol, triethylene glycol, propanediol, 1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, dimethylolheptane, dipropylene glycol, and 2,2,4-trimethyl-1,3-pentanediol, etc.), polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Examples of trihydric or higher aliphatic alcohols include sorbitol, 1,2,3,6-hexatetraol, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 2-methyl-1,2,3-propanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and glycerin.

[0033] Examples of the alicyclic polyhydric alcohols include alicyclic polyhydric alcohols having 6 to 12 carbon atoms (more specifically, 1,4-sorbitan, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, isosorbide, etc.), spiroglycol, tricyclodecanediol, tricyclodecanedimethanol, hydrogenated bisphenol A, hydrogenated bisphenol A ethylene oxide adduct, and hydrogenated bisphenol A propylene oxide adduct.

[0034] Examples of aromatic polyhydric alcohols include bisphenol A, alkylene oxide adducts of bisphenol A, p-xylylene glycol, para-xylene glycol, meta-xylene glycol, ortho-xylene glycol, 1,4-phenylene glycol, 1,3,5-trihydroxymethylbenzene, ethylene oxide adducts of 1,4-phenylene glycol, bisphenoxyethanolfluorene, and bis(4-(2-hydroxyethoxy)phenyl)fluorene.

[0035] Other examples of polyhydric alcohols include lactone-based polyester polyols obtained by ring-opening polymerization of lactones such as ε-caprolactone.

[0036] The polyhydric alcohol usable for the polymerization of the polyester resin preferably contains at least a bisphenol A alkylene oxide adduct. The bisphenol A alkylene oxide adduct is a relatively large molecule, which becomes a steric hindrance during crystallization. For this reason, by using the bisphenol A alkylene oxide adduct, it becomes difficult to form a crystalline region, and it is easy to obtain a non-crystalline polyester resin having a non-crystalline region. The number of moles of alkylene oxide added to bisphenol A is preferably 2 or more and 6 or less, more preferably 2.

[0037] Specific examples of bisphenol A alkylene oxide adducts include polyoxypropylene-(2.3)-2,2-bis(4-hydroxyphenyl)propane, polyoxyethylene-(2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene-(2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene-(2.2)-polyoxyethylene-(2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(6)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene-(2.2)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene-(2.4)-2,2-bis(4-hydroxyphenyl)propane, and polyoxypropylene-(3.3)-2,2-bis(4-hydroxyphenyl)propane.

[0038] The alkylene oxide adduct of bisphenol A is preferably an alkylene oxide adduct of bisphenol A having 2 to 4 carbon atoms, more preferably an ethylene oxide adduct of bisphenol A or a propylene oxide adduct of bisphenol A, still more preferably a propylene oxide adduct of bisphenol A, and particularly preferably a 2-mol propylene oxide adduct of bisphenol A.

[0039] The polyhydric alcohol usable for polymerization of the polyester resin preferably contains at least an aliphatic polyhydric alcohol. By containing an aliphatic polyhydric alcohol in the polyhydric alcohol, the glass transition point of the polyester resin can be suitably adjusted to a value within a predetermined range. As the aliphatic polyhydric alcohol, a dihydric aliphatic alcohol or a trihydric or higher aliphatic alcohol is preferable. As the dihydric aliphatic alcohol, ethylene glycol or diethylene glycol is preferable. As the trihydric or higher aliphatic alcohol, pentaerythritol, trimethylolpropane, or glycerin is preferable.

[0040] The polyhydric alcohol usable for polymerization of the polyester resin is preferably at least one polyhydric alcohol selected from the group consisting of bisphenol A alkylene oxide adducts, dihydric aliphatic alcohols, and trihydric or higher aliphatic alcohols, more preferably one to four polyhydric alcohols selected from this group, even more preferably two to four polyhydric alcohols selected from this group, and particularly preferably three or four polyhydric alcohols selected from this group. In this case, the selected polyhydric alcohol preferably includes a trihydric or higher aliphatic alcohol.

[0041] The polyhydric alcohol usable for polymerization of the polyester resin is preferably at least one polyhydric alcohol selected from the group consisting of bisphenol A alkylene oxide adduct (more specifically, bisphenol A propylene oxide adduct), ethylene glycol, pentaerythritol, trimethylolpropane, glycerin, and diethylene glycol, more preferably 1 to 4 polyhydric alcohols selected from this group, even more preferably 2 to 4 polyhydric alcohols selected from this group, and particularly preferably 3 or 4 polyhydric alcohols selected from this group. In this case, the selected polyhydric alcohol preferably contains one or both of trimellitic acid and pyromellitic acid.

[0042] The repeating unit derived from a bisphenol A alkylene oxide adduct, the repeating unit derived from ethylene glycol, the repeating unit derived from pentaerythritol, the repeating unit derived from trimethylolpropane, the repeating unit derived from glycerin, and the repeating unit derived from diethylene glycol are represented by the following general formula (3A), chemical formula (3B), (3C), (3D), (3E), and (3F), respectively. In the general formula (3A), R each represents a linear or branched alkylene group, m represents an integer of 0 or more, n represents an integer of 0 or more, and the sum of m and n is 2 or more and 6 or less. Each of R each preferably represents a linear or branched alkylene group having 2 to 4 carbon atoms, more preferably an ethylene group or a propylene group, and even more preferably a propylene group. The sum of m and n is preferably 2. The polyhydric alcohol that can be used in the polymerization of polyester resin has been described above.

[0043] [ka]

[0044] [ka]

[0045] (Repeating units derived from polycarboxylic acids) Examples of the repeating unit derived from a polyvalent carboxylic acid include a repeating unit derived from a divalent carboxylic acid and a repeating unit (third repeating unit) derived from a trivalent or higher carboxylic acid. As the repeating unit derived from a trivalent or higher carboxylic acid, a repeating unit derived from a trivalent or tetravalent carboxylic acid is preferable.

[0046] The repeating unit derived from the polycarboxylic acid contains at least a third repeating unit derived from a trivalent or higher carboxylic acid, and the content of the third repeating unit in the total amount (total substance amount) of the repeating units derived from the polycarboxylic acid is preferably 0.5 mol% to 9.0 mol%, more preferably 1.5 mol% to 9.0 mol%. In this case, the repeating unit derived from the polycarboxylic acid further contains a repeating unit derived from a divalent carboxylic acid in addition to the third repeating unit. Hereinafter, the "content of the third repeating unit derived from a trivalent or higher carboxylic acid in the total amount of the repeating units derived from the polycarboxylic acid" may be referred to as the "trivalent or higher carboxylic acid ratio". When the trivalent or higher carboxylic acid ratio is 0.5 mol% to 9.0 mol%, the acid value of the polyester resin is suitably adjusted to a value within a predetermined range.

[0047] The repeating unit derived from the polycarboxylic acid contains at least a fourth repeating unit derived from a polycarboxylic acid having a sulfonic acid group, and the content of the fourth repeating unit in the total amount (total substance amount) of the repeating units derived from the polycarboxylic acid is preferably higher than 0.0 mol% and not higher than 15.0 mol%, more preferably higher than 0.0 mol% and not higher than 10.0 mol%, and even more preferably higher than 0.0 mol% and not higher than 5.0 mol%. In this case, the repeating unit derived from the polycarboxylic acid further contains a repeating unit derived from a polycarboxylic acid having no sulfonic acid group in addition to the fourth repeating unit. Hereinafter, the "content of the fourth repeating unit derived from a polycarboxylic acid having a sulfonic acid group in the total amount of repeating units derived from the polycarboxylic acid" may be referred to as the "sulfonic acid unit ratio". When the sulfonic acid unit ratio is higher than 0.0 mol% and not higher than 15.0 mol%, the polyester resin is given appropriate hydrophilicity. As a result, the composite particles containing the polyester resin are well emulsified and dispersed in an aqueous medium, and an ink with excellent dispersibility is obtained. Furthermore, when the sulfonic acid unit ratio is more than 0.0 mol% and not more than 15.0 mol%, the polyester resin has the above-mentioned appropriate hydrophilicity, while also having an appropriate hydrophobicity to the extent that it is not dissolved in an aqueous medium. As a result, the polyester resin in the composite particles dissolves in an aqueous medium and adheres to the inside of the nozzle of the recording head of the inkjet textile printing device, which can prevent the nozzle from clogging. As a result, the ink is stably ejected from the nozzle, and the occurrence of image defects on the printed material is suppressed.

[0048] In another embodiment different from the above, it is also preferable that the repeating unit derived from the polycarboxylic acid does not contain a fourth repeating unit derived from a polycarboxylic acid having a sulfonic acid group. When the repeating unit derived from the polycarboxylic acid does not contain a fourth repeating unit, the polyester resin is given a suitable hydrophobicity to such an extent that it does not dissolve in an aqueous medium. As a result, it is possible to prevent the polyester resin in the composite particle from dissolving in an aqueous medium and adhering to the inside of the nozzle of the recording head of the inkjet textile printing device, causing the nozzle to become clogged. As a result, the ink is stably ejected from the nozzle, and the occurrence of image defects in the printed material is suppressed.

[0049] Since the acid value of the polyester resin can be easily adjusted to a value within a predetermined range, the polyester resin preferably has repeating units derived from two or more polycarboxylic acids, more preferably has repeating units derived from two or more and four or less polycarboxylic acids, and even more preferably has repeating units derived from three or four polycarboxylic acids.

[0050] Examples of polycarboxylic acids that can be used in the polymerization of polyester resins include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and tri- or higher carboxylic acids.

[0051] Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acids (such as 1,5-naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid), benzylmalonic acid, 4,4'-dicarboxydiphenyl ether, diphenic acid, and phenylenediacrylic acid.

[0052] Examples of the aliphatic dicarboxylic acid include malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, thiodipropionic acid, diglycolic acid, mesaconic acid, and citraconic acid.

[0053] Examples of the alicyclic dicarboxylic acid include 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, and adamantanedicarboxylic acid.

[0054] Examples of the trivalent or higher carboxylic acid include trivalent or higher aromatic carboxylic acids and trivalent or higher alicyclic carboxylic acids. Examples of the trivalent or higher aromatic carboxylic acids include trivalent or tetravalent aromatic carboxylic acids, more specifically, trimellitic acid, trimesic acid, and pyromellitic acid. Examples of the trivalent or higher alicyclic carboxylic acids include adamantanetricarboxylic acid.

[0055] The polycarboxylic acid usable for the polymerization of the polyester resin may have a sulfonic acid group. As the polycarboxylic acid having a sulfonic acid group, a dicarboxylic acid having a sulfonic acid group is preferable, and an aromatic dicarboxylic acid having a sulfonic acid group is more preferable. As the aromatic dicarboxylic acid having a sulfonic acid group, for example, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 2-sulfoterephthalic acid, 3,5-dicarbomethoxybenzenesulfonic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and 5-(4-sulfophenoxy)isophthalic acid, and metal salts thereof can be mentioned. As the metal salt, an alkali metal salt is preferable, and a sodium salt, a potassium salt, or a lithium salt is more preferable.

[0056] The polyvalent carboxylic acid usable for polymerization of the polyester resin is preferably at least one polyvalent carboxylic acid selected from the group consisting of aromatic divalent carboxylic acids, aromatic divalent carboxylic acids having three or more valences, and aromatic divalent carboxylic acids having a sulfonic acid group, more preferably one to four polyvalent carboxylic acids selected from this group, even more preferably two to four polyvalent carboxylic acids selected from this group, and particularly preferably three or four polyvalent carboxylic acids selected from this group. In this case, the selected polyvalent carboxylic acid preferably contains at least an aromatic carboxylic acid having three or more valences.

[0057] The polycarboxylic acid usable for polymerization of the polyester resin is preferably at least one polycarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, and sodium 5-sulfoisophthalate, more preferably one to four polycarboxylic acids selected from this group, even more preferably two to four polycarboxylic acids selected from this group, and particularly preferably three or four polycarboxylic acids selected from this group. In this case, the selected polycarboxylic acid preferably includes one or both of trimellitic acid and pyromellitic acid.

[0058] The repeating unit derived from sodium 5-sulfoisophthalate, the repeating unit derived from terephthalic acid, the repeating unit derived from isophthalic acid, the repeating unit derived from trimellitic acid, the repeating unit derived from pyromellitic acid, and the repeating unit derived from naphthalenedicarboxylic acid are represented by the following chemical formulas (1), (2A), (2B), (2C), (2D), and (2E), respectively. The repeating unit derived from naphthalenedicarboxylic acid is preferably represented by the following chemical formula (2F).

[0059] [ka]

[0060] [ka]

[0061] [ka]

[0062] The polycarboxylic acid usable for the polymerization of the polyester resin may be an alkyl ester of the polycarboxylic acid already described. As such an alkyl ester, an alkyl ester having 1 to 6 carbon atoms is preferable, an alkyl ester having 1 to 3 carbon atoms is more preferable, and a methyl ester is even more preferable. The polycarboxylic acid usable for the polymerization of the polyester resin has been described above.

[0063] The polyester resin constituting the composite particles will be further described below. The repeating unit derived from the polyvalent carboxylic acid preferably contains at least a fifth repeating unit derived from a polyvalent carboxylic acid having an aromatic hydrocarbon. The repeating unit derived from the polyhydric alcohol preferably contains at least a sixth repeating unit derived from a polyhydric alcohol having an aromatic hydrocarbon. The total content of the fifth repeating unit and the sixth repeating unit in the total amount of the repeating units derived from the polyvalent carboxylic acid and the repeating units derived from the polyhydric alcohol is preferably 50 mol% or more. Hereinafter, the "total content of the fifth repeating unit derived from the polyvalent carboxylic acid having an aromatic hydrocarbon and the sixth repeating unit derived from the polyhydric alcohol having an aromatic hydrocarbon in the total amount of the repeating units derived from the polyvalent carboxylic acid and the repeating units derived from the polyhydric alcohol" may be referred to as the "aromatic ratio". When the aromatic ratio is 50 mol% or more, the glass transition point of the polyester resin is suitably adjusted to a value within a predetermined range. In addition, the disperse dye contained in the composite particles often contains aromatic hydrocarbons. Therefore, when the aromatic ratio is 50 mol% or more, the aromatic hydrocarbons of the disperse dye and the aromatic hydrocarbons of the polyester resin are stacked to enhance the interaction, and the disperse dye and the polyester resin are easily complexed. The aromatic ratio is more preferably 50 mol % or more and 90 mol % or less, even more preferably 50 mol % or more and 80 mol % or less, and even more preferably 50 mol % or more and 65 mol % or less.

[0064] The tri- or higher carboxylic acid ratio, EG ratio, tri- or higher carboxylic acid ratio, sulfonic acid unit ratio, and aromatic ratio, which have already been described, can each be measured, for example, by analyzing the polyester resin using a nuclear magnetic resonance (NMR) apparatus and obtaining the ratio of peaks characteristic of each repeating unit.

[0065] In order to obtain a non-crystalline polyester resin having a high content of non-crystalline regions, it is preferable to select the polyhydric alcohol and polycarboxylic acid monomers so as not to form regularity for forming crystalline regions. The higher the content of non-crystalline regions in the non-crystalline polyester resin, the easier it is to dye the non-crystalline polyester resin with a disperse dye, and the easier it is to produce composite particles.

[0066] The polyester resin is produced by condensation polymerization of at least one polyhydric alcohol and at least one polyvalent carboxylic acid. The temperature for condensation polymerization is preferably 220°C or higher and 250°C or lower. When the temperature for condensation polymerization is 220°C or higher, the productivity of the polyester resin is good. When the temperature for condensation polymerization is 250°C or lower, the decomposition of the polyester resin can be suppressed, and volatile components are less likely to be generated. The temperature for condensation polymerization is preferably set in consideration of the composition ratio of the monomers. For example, when the content of alkylene oxide adduct of bisphenol A in the monomer is low, when the content of trivalent or higher carboxylic acid in the monomer is low, and when the ratio of the number of hydroxyl groups to the number of carboxyl groups in the monomer is low, the reaction is likely to proceed, so the temperature for condensation polymerization can be set low. The polyester resin constituting the composite particle has been described above.

[0067] (Disperse dyes that compose composite particles) The disperse dye constituting the composite particles is not particularly limited. The disperse dye has low hydrophilicity. However, by forming a complex with a polyester resin having a carboxyl group and a hydroxyl group, which are hydrophilic groups, the composite particles containing the disperse dye can be well emulsified and dispersed in an aqueous medium.

[0068] In addition, disperse dyes often have one or both of a nitro group and a quinone structure. The nitro group and the quinone structure have a high affinity for the ester bond of the polyester resin. Therefore, when the amorphous region of the polyester resin softens with an increase in temperature and the entanglement of the resin chain weakens, the disperse dye easily penetrates into the amorphous region along the resin chain. Therefore, the disperse dye can be complexed with the polyester resin by a simple method (for example, a method of kneading the disperse dye with the polyester resin without using a solvent or a dispersant).

[0069] In addition, it is usually difficult to print cotton fabric using disperse dyes. However, because the cotton fabric and the composite particles are bonded to each other via the polyester resin in the composite particles, printing on cotton fabric is possible even when disperse dyes are used. Therefore, printing is possible regardless of the type of object to be printed (e.g., cotton fabric and polyester fabric) even when disperse dyes are used.

[0070] Disperse dyes include, for example, CI Disperse Yellow 51, 54, and 60; CI Disperse Orange 5, 7, 20, and 23; CI Disperse Red 50, 53, 59, 60, 239, and 240; CI Disperse Violet 8, 11, 17, 26, 27, 28, and 36; CI Disperse Blue 3, 5, 26, 35, 55, 56, 72, 81, 91, 108, and 359; CI Disperse Yellow 42, 49, 76, 83, 88, 93, 99, 119, 126, 160, 163, 165, 180, 183, 186, 198, 199, 200, 224, and 237; CI Disperse Orange 29, 30, 31, 38, 42, 44, 45, 53, 54, 5 5, 71, 73, 80, 86, 96, 118, and 119; CI Disperse Red 73, 88, 91, 92, 111, 127, 131, 143, 145, 146, 152, 153, 154, 179, 191, 192, 206, 221, 258, 283, 302, 323, 328, and 359; CI Disperse Violet 26, 35 , 48, 56, 77, and 97; and CI Disperse Blue 27, 54, 60, 73, 77, 79, 79:1, 87, 143, 165, 165:1, 165:2, 181, 185, 197, 225, 257, 266, 267, 281, 341, 353, 354, 358, 364, 365, 368, 359, and 360.

[0071] In addition, a disperse dye toned to black by mixing multiple colors of disperse dyes may be used. For example, a disperse dye obtained by blending an orange disperse dye and a red disperse dye with a blue disperse dye as the main component may be used as a black disperse dye. In addition, the color tone may be finely adjusted by further blending a disperse dye other than orange and red with such a black disperse dye.

[0072] Since the disperse dye is suitable for the heating step during printing, it is preferable that the disperse dye is a disperse dye having thermal transferability. As the disperse dye having thermal transferability, CI Disperse Yellow 51, 54, and 60; CI Disperse Orange 5, 7, 20, and 23; CI Disperse Red 50, 53, 59, 60, 239, and 240; CI Disperse Violet 8, 11, 17, 26, 27, 28, and 36; and CI Disperse Blue 3, 5, 26, 35, 55, 56, 72, 81, 91, 108, and 359 are preferable.

[0073] In order to suppress unevenness in the printed image, it is preferable that the disperse dye is molecularly dispersed along the amorphous regions of the polyester resin in the composite particles. For the same reason, it is preferable that the disperse dye is uniformly dispersed in the polyester resin in the composite particles. The amorphous regions of the polyester resin are easily dyed with the disperse dye. Therefore, if the amorphous regions are uniformly arranged in the polyester resin, it is easy to obtain composite particles in which the disperse dye is uniformly dispersed in the polyester resin.

[0074] The content of the disperse dye is preferably 0.5% by mass or more and 10.0% by mass or less, more preferably 1.0% by mass or more and 7.0% by mass or less, and even more preferably 1.0% by mass or more and 4.0% by mass or less, based on the mass of the ink. When the content of the disperse dye is 0.5% by mass or more based on the mass of the ink, sufficient image density can be ensured in the printed image. When the content of the disperse dye is 10.0% by mass or less based on the mass of the ink, sufficient saturation can be ensured in the printed image.

[0075] In order to print an image with sufficient image density, the content of the disperse dye in the composite particles is preferably more than 0% by mass and not more than 50% by mass, and more preferably from 1% by mass to 20% by mass.

[0076] <Crosslinking agent> The crosslinking agent includes a blocked isocyanate. The object to be printed and the composite particles are crosslinked via the blocked isocyanate, which is a crosslinking agent, and the abrasion fastness of the image printed on the object to be printed is further improved. The crosslinking reaction by the blocked isocyanate will be described later in the third embodiment.

[0077] Here, an isocyanate is a compound having a -N=C=O group. A blocked isocyanate is an isocyanate in which the reactive group -N=C=O group is blocked with a blocking agent. The -N=C=O group blocked with a blocking agent is represented by the chemical formula "-NHCOA". In the chemical formula "-NHCOA", A represents a group derived from the blocking agent (AH). A blocked isocyanate is a compound having at least two (for example, two) groups represented by the chemical formula "-NHCOA".

[0078] As the blocked isocyanate, commercially available products can be used. Specific examples of the blocked isocyanate include Meikanate CX, SU-268A, NBP-873D, NBP-211, Meikanate TP-10, DM-6400, Meikanate DM-3031CONC, and Meikanate DM-350Z manufactured by Meisei Chemical Industry Co., Ltd.

[0079] In order to improve the abrasion fastness of the printed image, the blocked isocyanate is dispersed in the ink, for example in the form of latex particles. The content of the blocked isocyanate is preferably 0.1% by mass or more and 10.0% by mass or less relative to the mass of the ink.

[0080] <Neutralizing agent> By containing a neutralizing agent in the ink, the carboxyl groups of the polyester resin in the composite particles are ionized, and the composite particles are stably emulsified and dispersed. -Examples of the neutralizing agent include aqueous ammonia, an alkaline aqueous solution (e.g., an aqueous sodium hydroxide solution), allylamine, isopropylamine, diisopropylamine, ethylamine, diethylamine, triethylamine, 2-ethylhexylamine, 3-ethoxypropylamine, diisobutylamine, 3-diethylaminopropylamine, tri-n-octylamine, t-butylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, n-propanolamine, butanolamine, 2-amino-4-pentanol, 2-amino-3-hexanol, 5-amino-4-octanol, 3 -amino-3-methyl-2-butanol, monoethanolamine, N,N-dimethylethanolamine, isopropanolamine, neopentanolamine, diglycolamine, ethylenediamine, 1,3-diaminopropane, 1,2-diaminopropane, 1,6-diaminohexane, 1,9-diaminononane, 1,12-diaminododecane, dimeric fatty acid diamine, 2,2,4,-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, hexamethylenediamine, N-aminoethylpiperazine, N-aminopropylpiperazine, N-aminopropyldipiperidipropane, and piperazine. As the neutralizing agent, ammonia water or an aqueous sodium hydroxide solution is preferable.

[0081] The content of the neutralizing agent is preferably an amount that can neutralize the acid value of the polyester resin. The content of the neutralizing agent is not particularly limited, but is preferably an amount that makes the degree of neutralization of the polyester resin 50% or more, more preferably an amount that makes the degree of neutralization of the polyester resin 60% or more. The degree of neutralization is calculated from the formula "degree of neutralization (%) = 100 - (moles of acid groups after neutralization / moles of acid groups before neutralization) x 100".

[0082] In order to stably emulsify and disperse the composite particles, the content of the neutralizer is preferably 0.1% by mass or more and 5.0% by mass or less with respect to the mass of the ink.

[0083] <Aqueous medium> The aqueous medium is a medium containing water as a main component. The aqueous medium may function as a solvent or as a dispersion medium. Specific examples of the aqueous medium include water, or a mixture of water and a hydrophilic organic solvent. Examples of the hydrophilic organic solvent contained in the aqueous medium include ketone solvents (more specifically, acetone, etc.), alcohol solvents (more specifically, methanol, ethanol, isopropyl alcohol, etc.), and glycol ether solvents (more specifically, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, ethylene glycol monotertiary butyl ether, etc.). The content of water in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0084] The content of the aqueous medium is preferably 5% by mass or more and 99% by mass or less, and more preferably 50% by mass or more and 90% by mass or less, based on the mass of the ink. When the content of the aqueous medium is within this range, an ink having an appropriate viscosity can be obtained.

[0085] <Surfactant> The ink may contain a surfactant as necessary. By containing a surfactant in the ink, an ink having excellent wettability to a printing object can be obtained. Examples of the surfactant include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants.

[0086] The surfactant is preferably a nonionic surfactant, more preferably a surfactant having an acetylene glycol structure, and even more preferably an acetylene diol ethylene oxide adduct. The HLB value of the surfactant is preferably 1 or more and 5 or less. The HLB value of the surfactant is calculated, for example, by the Griffin method using the formula "HLB value = 20 x (sum of formula weights of hydrophilic parts) / molecular weight".

[0087] The surfactant content is preferably 0.01% by mass or more and 0.50% by mass or less with respect to the mass of the ink. When the surfactant content is within this range, an ink having excellent dispersion stability of the composite particles can be obtained. In addition, when the surfactant content is 0.50% by mass or less, air bubbles are unlikely to be generated from the ink in the nozzle of the recording head of the inkjet printing device, and the ink can be stably discharged from the nozzle.

[0088] <Moisturizer> The ink may contain a humectant as necessary. If the ink contains a humectant, the volatilization of liquid components from the ink can be suppressed. Examples of the humectant include sorbitol, polyalkylene glycols, alkylene glycols, and glycerin. Examples of the polyalkylene glycols include polyethylene glycol and polypropylene glycol. Examples of the alkylene glycols include 3-methyl-1,5-pentanediol, ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, dipropylene glycol, trimethylene glycol (i.e., 1,3-propanediol), triethylene glycol, tripropylene glycol, 1,2,6-hexanetriol, thiodiglycol, 1,3-butanediol, and 1,5-pentanediol. The humectant is preferably one or both of alkylene glycols and glycerin, and more preferably one or both of propylene glycol and glycerin. The content of the humectant relative to the mass of the ink is preferably 0.1% by mass to 30.0% by mass, and more preferably 20.0% by mass to 30.0% by mass.

[0089] <Additives> The ink may further contain additives (more specifically, a viscosity modifier, a dissolution stabilizer, a penetrating agent, an antioxidant, an ultraviolet absorbing agent, etc.) as necessary.

[0090] It is preferable that the ink does not contain a pigment. By not containing a pigment with a relatively large particle size, it is possible to suppress stiffness of the printed material and improve the friction fastness. In addition, it is possible to suppress the decrease in image density and saturation caused by the penetration of particulate pigment into the interior of the printed object (for example, into the fibers of the cloth).

[0091] [Second embodiment: Ink manufacturing method] Next, a method for producing an ink according to a second embodiment of the present invention will be described. The ink according to the first embodiment is produced by the method for producing the ink according to the second embodiment. The method for producing an ink according to the second embodiment includes, for example, a kneading step, a composite particle forming step, and a mixing step.

[0092] (Kneading process) In the kneading step, the polyester resin and the disperse dye are kneaded to obtain a kneaded product. For example, a kneader (more specifically, a single-screw extruder, a twin-screw extruder, etc.) is used for the kneading. The obtained kneaded product of the polyester resin and the disperse dye may be pulverized as necessary.

[0093] Instead of the kneading step, an alternative step (more specifically, a step of mixing the polyester resin and the disperse dye while dissolving them in a solvent, or a step of polymerizing the monomer in a solution in which the monomer for forming the polyester resin and the disperse dye are dissolved, etc.) may be performed. However, in the method of kneading the polyester resin and the disperse dye, the disperse dye is less likely to separate and precipitate during phase inversion emulsification, which will be described later, compared to the method of performing the alternative step. Therefore, it is preferable to perform the above kneading step.

[0094] (Composite particle formation process) In the composite particle forming step, the oil phase and the aqueous phase are emulsified by phase inversion to form the composite particles. The oil phase contains the kneaded product obtained in the kneading step and an organic solvent. The aqueous phase contains water.

[0095] Specifically, the kneaded material, the organic solvent, and optionally a neutralizing agent are placed in a reactor, and the kneaded material is dissolved in the organic solvent to obtain an oil phase (a solution phase of the organic solvent). The obtained oil phase contains the kneaded material, the organic solvent, and optionally a neutralizing agent.

[0096] Next, water is added to the oil phase in the reactor to form an aqueous phase. The aqueous phase contains water. After the addition of water, the oil phase becomes the continuous phase and the aqueous phase becomes the dispersed phase. That is, the liquid phase in the reactor becomes a water-in-oil (W / O) type emulsion in which the aqueous phase in droplet form is dispersed in the oil phase.

[0097] Next, the oil phase and the aqueous phase in the reactor are stirred to invert and emulsify the oil phase and the aqueous phase. The oil phase and the aqueous phase are stirred, for example, by a stirring device. After the phase inversion emulsification, the aqueous phase becomes the continuous phase, and the oil phase becomes the dispersed phase. That is, the liquid phase in the reactor becomes the liquid phase of an oil-in-water (O / W) type emulsion in which the oil phase in droplet form is dispersed in the aqueous phase. The oil phase in droplet form becomes the composite particles, which are emulsified particles. If necessary, the organic solvent in the oil phase is distilled off under reduced pressure to obtain an aqueous dispersion of the composite particles.

[0098] The organic solvent contained in the oil phase is preferably a solvent having a ketone structure, more preferably acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, methyl isobutyl ketone, or methyl isopropyl ketone, and particularly preferably methyl ethyl ketone. By using such an organic solvent, the kneaded material can be easily dissolved in the organic solvent, and the organic solvent can be easily removed by distillation after phase inversion emulsification.

[0099] In the composite particle forming step, it is preferable to add a neutralizing agent to the oil phase before adding the water phase to the oil phase to ionize the carboxyl group of the polyester resin contained in the kneaded product. The ionization of the carboxyl group increases the affinity between the polyester resin in the oil phase and the water phase, and allows the phase inversion emulsification to proceed favorably. The temperature of the oil phase when the neutralizing agent is added is preferably a temperature below the boiling point of the organic solvent, more preferably 75°C or less. In addition, if the phase inversion emulsification proceeds without any problems, the addition of the neutralizing agent can be omitted.

[0100] In the oil phase before the addition of the aqueous phase, the content of the kneaded material is preferably 5% by mass or more and 70% by mass or less, more preferably 10% by mass or more and 60% by mass or less, and even more preferably 10% by mass or more and 50% by mass or less. When the content of the kneaded material is within such a range, the particle size of the composite particles formed from the kneaded material can be easily controlled, and the composite particles can be efficiently produced.

[0101] The temperature of the water phase and the oil phase is preferably equal to or higher than the glass transition point of the polyester resin. At a temperature equal to or higher than the glass transition point, the non-crystalline regions of the polyester resin in the kneaded product are softened, the entanglement of the resin chains is weakened, and the disperse dye penetrates further into the non-crystalline regions along the resin chains. As a result, the compatibility of the disperse dye and the polyester resin in the kneaded product is further increased.

[0102] Whether or not the disperse dye has been introduced into the polyester resin can be confirmed by the following method. That is, after the composite particles are formed, the aqueous medium containing the composite particles is collected. Using a centrifuge, the aqueous medium containing the composite particles is centrifuged at a rotation speed of 15,000 rpm for 30 minutes. After centrifugation, the supernatant is collected. Using a spectrophotometer (e.g., manufactured by Hitachi, Ltd.), the amount of disperse dye contained in the supernatant is quantified by absorbance method. The amount of disperse dye contained in the supernatant corresponds to the amount of disperse dye not introduced into the polyester resin.

[0103] (Mixing process) In the mixing step, the composite particles, the aqueous medium, and the crosslinking agent are mixed. For example, a stirrer is used for mixing. Note that ink components (more specifically, at least one selected from the group consisting of surfactants, humectants, and additives) may be further added and mixed as necessary. The resulting mixture is filtered as necessary. As a result, ink is obtained. The method for producing ink according to the second embodiment has been described above.

[0104] [Third embodiment: Inkjet printing method] A third embodiment of the present invention relates to an inkjet textile printing method. The inkjet textile printing method of the third embodiment includes, for example, a discharging step. In the discharging step, ink is discharged from a discharge surface of a recording head to a printing target. The discharged ink is the ink of the first embodiment.

[0105] In order to improve the abrasion fastness of the printed image, the inkjet printing method of the third embodiment preferably further includes a heating step in addition to the ejection step. In the heating step, the ink that has landed on the printing target is heated.

[0106] The ink of the first embodiment is used in the inkjet textile printing method of the third embodiment. As already mentioned, the ink of the first embodiment is excellent in dispersibility and storage stability. Therefore, according to the inkjet textile printing method of the third embodiment using such an ink, aggregation of the ink in the inkjet textile printing device is suppressed. Also, as already mentioned, the ink of the first embodiment can print an image with few image defects and excellent friction fastness, and can suppress deterioration of the tactile feel of the printed textile. Therefore, according to the inkjet textile printing method of the third embodiment using such an ink, it is possible to print an image with few image defects and excellent friction fastness, and can suppress deterioration of the tactile feel of the printed textile.

[0107] Moreover, the inkjet printing method of the third embodiment has the advantage over the sublimation printing method that there is no restriction on the molecular weight of the disperse dye used since there is no need to perform sublimation transfer in a short time, and there is no limitation on the molecular weight of the disperse dye used since no transfer paper is used. Note that the sublimation printing method is a method in which ink is ejected onto transfer paper using an inkjet printing device, and then the sublimation dye in the ink is sublimated and transferred from the transfer paper to the printing object by heating.

[0108] Furthermore, the inkjet printing method of the third embodiment has the advantage that bleeding of the disperse dye that spreads due to capillary action along the fibers to be printed is less likely to occur compared to the case of using an ink containing a disperse dye that is not complexed, making it possible to form an image with sharp edges, and eliminating the need for post-processing to wash away unfixed disperse dye.

[0109] Hereinafter, an example of the inkjet textile printing method according to the third embodiment will be specifically described with reference to Fig. 1. Fig. 1 shows an example of an inkjet textile printing device used in the inkjet textile printing method according to the third embodiment.

[0110] The inkjet printing apparatus 10 shown in Fig. 1 includes a feed section 11, an ink discharge section 12, a drying section 14, a heating processing section 15, and a recovery section 17. A printing object P1 is set in the inkjet printing apparatus 10. In Fig. 1, the printing object before the printing of an image is completed is shown as the printing object P1, and the printing object after the printing of the image is completed is shown as the printing object P2. The feed section 11, the ink discharge section 12, the drying section 14, the heating processing section 15, and the recovery section 17 are arranged in the conveying direction of the printing object P1 in the order shown.

[0111] The feeding section 11 feeds the printing object P1 to the ink ejection section 12.

[0112] The ink ejection unit 12 ejects ink onto the printing object P1 fed out from the feed unit 11. The ink ejection unit 12 includes a recording head 13. Ink is ejected from the recording head 13 (more specifically, the ejection surface of the recording head 13) onto the printing object P1 (more specifically, the image forming area of ​​the printing object P1). The recording head 13 is not particularly limited, but is, for example, a piezoelectric head or a thermal inkjet head.

[0113] The drying section 14 dries the ink ejected onto the printing object P1.

[0114] The heat treatment section 15 performs a heat treatment on the ink ejected onto the printing object P1. The heat treatment section 15 includes a heating roller 16a and a pressure roller 16b. The heating roller 16a has a heat source therein and heats the printing object P1. The pressure roller 16b is in pressure contact with the heating roller 16a via the printing object P1.

[0115] The recovery unit 17 recovers, while winding up, the printing object P1 that has been subjected to a heat treatment and has been printed, i.e., the printing material P2. One end of the printing object P1 is set in the reel-out unit 11, and the other end is set in the recovery unit 17. Therefore, as the recovery unit 17 recovers the printing object P1 while winding it up, the printing object P1 is reeled out from the reel-out unit 11 in conjunction with this.

[0116] The printing object P1 may be a woven fabric or a knitted fabric. Examples of the printing object P1 include cotton fabric, silk fabric, linen fabric, acetate fabric, rayon fabric, nylon fabric, polyurethane fabric, and polyester fabric.

[0117] A method of printing an image on a printing object P1 will be described using the inkjet printing apparatus 10 shown in Fig. 1. First, the delivery section 11 delivers the printing object P1 stored therein to the ink ejection section 12.

[0118] Next, the ejection process is performed. In the ejection process, when the image forming area of ​​the printing object P1 reaches a position facing the recording head 13 of the ink ejection unit 12, ink is ejected from the recording head 13 (more specifically, from the nozzle openings provided on the ejection surface of the recording head 13) onto the printing object P1.

[0119] Next, a drying process is performed as necessary. In the drying process, the area of ​​the printing object P1 where the ink has landed is dried by the drying section 14. The drying temperature of the drying section 14 is, for example, lower than the heat treatment temperature of the heat treatment section 15 described later. The drying temperature of the drying section 14 is, for example, lower than the crosslinking temperature. The crosslinking temperature is a temperature at which the hydroxyl group of the printing object P1 and the hydroxyl group of the polyester resin contained in the composite particles are crosslinked by a crosslinking agent. By performing the drying process, the ink on the printing object P1 can be dried to such an extent that it does not adhere to the pressure roller 16b during the heating process described later.

[0120] Next, a heating step is performed. In the heating step, the ink that has landed on the printing target P1 is heated. Specifically, the area of ​​the printing target P1 on which the ink has landed passes through the nip portion between the heating roller 16a and the pressure roller 16b. At this time, the printing target P1 on which the ink has landed is heated and pressurized.

[0121] The heating temperature of the heat treatment section 15 is, for example, higher than the crosslinking temperature. The heating temperature of the heat treatment section 15 is, for example, 120° C. or higher and 200° C. or lower. The heating time is, for example, 1 minute or higher and 10 minutes or lower.

[0122] The ink on the printing object P1 is heated at a temperature higher than the crosslinking temperature, thereby inducing a crosslinking reaction by the crosslinking agent. Specifically, the printing object P1 has, for example, a hydroxyl group. The polyester resin contained in the composite particles in the ink also has a hydroxyl group. When the ink is heated, the hydroxyl group of the printing object P1 and the hydroxyl group of the polyester resin contained in the composite particles in the ink are crosslinked by the crosslinking agent (blocked isocyanate). As a result, the printing object P1 and the composite particles are bonded together via the crosslinking agent.

[0123] The crosslinking reaction caused by the blocked isocyanate, which is a crosslinking agent, will be described in detail below. As described in the first embodiment, the blocked isocyanate is a compound having at least two (for example, two) groups represented by the chemical formula "-NHCOA". When the ink is not heated, the -NHCO group is blocked with the group A derived from the blocking agent, so the -NHCOA group does not react with the hydroxy group. However, when the ink is heated, the group A derived from the blocking agent is released from the -NHCOA group, and a reactive group, -N=C=O group, is formed, which reacts with the hydroxy group (-OH). Specifically, the reaction represented by the reaction formula "-OH+-NHCOA→-OH+-N=C=O+AH→-OCONH-+AH" proceeds. As a result, a crosslinked structure represented by the chemical formula "-OCONH-" is formed, and the blocking agent (AH) is released. A part of the -N=C=O groups of the blocked isocyanate formed by heating reacts with the hydroxy group of the printing object P1. This reaction causes the hydroxy group of the printing object P1 to bond with the blocked isocyanate via a crosslinked structure (-OCONH-). The remaining -N=C=O group reacts with the hydroxy group of the polyester resin contained in the composite particles in the ink. This reaction causes the hydroxy group of the polyester resin contained in the composite particles in the ink to bond with the blocked isocyanate via a crosslinked structure (-OCONH-). In this way, the printing object P1 and the composite particles are bonded with the blocked isocyanate, which is a crosslinking agent, and two crosslinked structures. As a result, the disperse dye contained in the composite particles is less likely to be detached from the printing object P1, and the abrasion fastness of the printed image is improved. The crosslinking reaction caused by the blocked isocyanate, which is a crosslinking agent, has been described above.

[0124] Benefits other than the above-mentioned crosslinking reaction can be obtained by heating the ink on the printing object P1 by the heat treatment unit 15. For example, when the printing object P1 is a polyester fiber fabric formed of a polyester resin having a non-crystalline region, by heating the ink on the printing object P1 by the heat treatment unit 15, a part of the disperse dye contained in the composite particles in the ink moves to the non-crystalline region of the polyester resin of the polyester fiber fabric, and the polyester fiber fabric and the disperse dye can be integrated.

[0125] By carrying out the heating step, a printing object P1 on which an image is printed, that is, a printing object P2 is formed. The printing object P2 is collected in a collecting section 17 while being wound up.

[0126] An example of the inkjet printing method according to the third embodiment has been described above with reference to FIG. 1. However, the inkjet printing method according to the third embodiment is not limited to the above method, and can be modified, for example, as in the following first to eighth modified examples. Regarding the first modified example, a pretreatment may be performed on the printing object P1 before ejecting ink onto the printing object P1. By performing the pretreatment, bleeding of the printed image is suppressed, and an image with high color development and clarity can be printed. Regarding the second modified example, if the image can be printed satisfactorily, the drying step may be omitted. Regarding the third modified example, if the image with the desired friction fastness can be printed, the heating step may be omitted. Regarding the fourth modified example, instead of the heat treatment unit 15 including the heating roller 16a and the pressure roller 16b, a drying device that blows hot air onto the printing object P1, or a steam heating device may be used. Regarding the fifth modified example, the heat treatment unit 15 does not have to be provided in the inkjet printing device 10. For example, after printing an image on the printing object P1 using the inkjet printing apparatus 10, the printing object P1 on which the ink has landed may be heated using a heating device independent of the inkjet printing apparatus 10 (i.e., different from the inkjet printing apparatus 10). Regarding the sixth modified example, in order to improve the fastness of the printed image, the printed material P2 on which the image has been printed may be further subjected to a metal ion treatment, an acid treatment, or an alkali treatment. Regarding the seventh modified example, the ink ejection section 12 includes one recording head 13, but may include multiple recording heads 13. Regarding the eighth modified example, a flatbed type inkjet printing apparatus may be used instead of the inkjet printing apparatus 10. Regardless of the type of inkjet printing apparatus, the effect of the present invention can be obtained by using the ink according to the first embodiment. EXAMPLES

[0127] Next, examples of the present invention will be described. In the evaluation in which an error occurs, a sufficient number of measurements were obtained so that the error was sufficiently small, and the arithmetic average of the obtained measurements was used as the evaluation value. In the following description, "parts by mass" may be written as "parts".

[0128] [Preparation of polyester resin] Amorphous polyester resins (A1) to (A6) and (B1) to (B9) and crystalline polyester resin (B10) (hereinafter referred to as resins (A1) to (A6) and (B1) to (B10), respectively) were prepared. The monomers used to produce the resins (A1) to (A6) and (B1) to (B9) are shown in Table 1. The substance amounts (unit: mol) of the repeating units, the contents of the repeating units, the glass transition points, the acid values, and the hydroxyl values ​​of the resins (A1) to (A6) and (B1) to (B9) are shown in Tables 2 and 3. The resin (B10) will be described later.

[0129] [Table 1]

[0130] [Table 2]

[0131] [Table 3]

[0132] The monomer name in the "amount of monomer" column in Table 1 means the name of the monomer used to produce the resin. Meanwhile, the monomer name in the "amount of repeating unit" column in Tables 2 and 3 means the repeating unit derived from the corresponding monomer. For example, "terephthalic acid" in Table 1 means terephthalic acid, and "terephthalic acid" in Tables 2 and 3 means the repeating unit derived from terephthalic acid.

[0133] The meanings of the terms in Tables 1 to 3 other than those mentioned above are as follows. Amount of monomer: The mass (in parts) of the corresponding monomer used to produce the resin. Amount of repeating unit: The amount of substance of the corresponding repeating unit contained in the resin (unit: mol). NDC: dimethyl 2,6-naphthalenedicarboxylate. SSIP: Sodium 5-sulfoisophthalate. EG: ethylene glycol. BPA-PO: Bisphenol A propylene oxide 2 mole adduct. -: The corresponding monomer is not added, or the corresponding repeating unit is not present. Tg: glass transition temperature (unit: °C).

[0134] Next, there will be described a method for calculating the contents of repeating units shown in Tables 2 and 3. In the calculation formulas described later, M1 to M12 have the following meanings. M1: Amount of repeating units derived from terephthalic acid (unit: mol). M2: Amount of repeating units derived from isophthalic acid (unit: mol). M3: Amount of repeating units derived from trimellitic acid (unit: mol). M4: Amount of repeating units derived from pyromellitic acid (unit: mol). M5: Amount of repeating units derived from dimethyl 2,6-naphthalenedicarboxylate (unit: mol). M6: Amount of repeating units derived from sodium 5-sulfoisophthalate (unit: mol). M7: Amount of repeating units derived from ethylene glycol (unit: mol). M8: Amount of repeating units derived from bisphenol A propylene oxide 2 mole adduct (unit: mol). M9: Amount of repeating units derived from diethylene glycol (unit: mol). M10: Amount of repeating units derived from pentaerythritol (unit: mol). M11: Amount of repeating units derived from trimethylolpropane (unit: mol). M12: Amount of repeating units derived from glycerin (unit: mol).

[0135] The percentage of tri- or higher carboxylic acids was calculated using the formula "(percentage of tri- or higher carboxylic acids) = 100 × (amount of third repeating units derived from tri- or higher carboxylic acids) / (total amount of repeating units derived from polycarboxylic acids) = 100 × (M3 + M4) / (M1 + M2 + M3 + M4 + M5 + M6)".

[0136] The percentage of trihydric or higher alcohols was calculated using the formula "(percentage of trihydric or higher alcohols) = 100 × (amount of first repeating unit derived from trihydric or higher alcohols) / (total amount of repeating units derived from polyhydric alcohols) = 100 × (M10 + M11 + M12) / (M7 + M8 + M9 + M10 + M11 + M12)".

[0137] The EG ratio was calculated using the formula: (EG ratio) = 100 × (amount of second repeating units derived from ethylene glycol) / (total amount of repeating units derived from polyhydric alcohol) = 100 × (M7) / (M7 + M8 + M9 + M10 + M11 + M12).

[0138] The sulfonic acid unit ratio was calculated according to the formula "(sulfonic acid unit ratio) = 100 × (amount of the fourth repeating unit derived from a polycarboxylic acid having a sulfonic acid group) / (total amount of repeating units derived from a polycarboxylic acid) = 100 × (M6) / (M1 + M2 + M3 + M4 + M5 + M6)".

[0139] The aromatic ratio was calculated by the formula: (aromatic ratio) = 100 x [(amount of the 5th repeating unit derived from polycarboxylic acid having aromatic hydrocarbon) + (amount of the 6th repeating unit derived from polyhydric alcohol having aromatic hydrocarbon)] / [(total amount of repeating units derived from polycarboxylic acid) + (total amount of repeating units derived from polyhydric alcohol)] = 100 x [(M1 + M2 + M3 + M4 + M5 + M6) + (M8)] / [(M1 + M2 + M3 + M4 + M5 + M6) + (M7 + M8 + M9 + M10 + M11 + M12)]. Next, the method for preparing the resin will be described.

[0140] <Preparation of Resin (A1)> A four-neck flask equipped with a distillation tube, a nitrogen inlet tube, a thermometer, and a stirring blade was prepared. In the flask, terephthalic acid (60 parts), isophthalic acid (39 parts), pyromellitic acid (1 part), ethylene glycol (33 parts), bisphenol A propylene oxide 2 mole adduct (63 parts), diethylene glycol (2 parts), and trimethylolpropane (2 parts) were placed as monomers, and tetrabutoxytitanium (0.1 parts) was placed as a reaction catalyst. The contents of the flask were heated to 130°C. Furthermore, the contents of the flask were heated from 130°C to 170°C over 2 hours. Furthermore, the contents of the flask were gradually heated from 170°C to 250°C, while gradually reducing the pressure from normal pressure to 5mmHg. The monomers in the flask were condensed and polymerized at a temperature of 250°C and a reduced pressure of 5mmHg to obtain a resin (A1).

[0141] <Preparation of Resins (A2) to (A6) and (B1) to (B9)> Resins (A2) to (A6) and (B1) to (B9) were each prepared in the same manner as resin (A1), except that the types and amounts (units: parts) of monomers shown in Table 1 were used.

[0142] <Preparation of Resin (B10)> A 5L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was prepared. 1,4-butanediol (25.00 mol), fumaric acid (23.75 mol), trimellitic anhydride (1.65 mol), and hydroquinone (5.3 g) were placed in the flask, and the contents of the flask were reacted at 160°C for 5 hours. Next, the internal temperature of the flask was increased to 200°C, and the contents of the flask were reacted at 200°C for 1 hour. Next, the pressure inside the flask was reduced to 8.3 KPa, and the contents of the flask were reacted at 200°C for 1 hour. In this way, resin (B10) was obtained. The acid value of resin (B10) was 24 mgKOH / g, and the hydroxyl value was 28 mgKOH / g.

[0143] <Measurement of glass transition point and melting point> The glass transition points and melting points of the obtained resins (A1) to (A6) and (B1) to (B10) were measured using a differential scanning calorimeter ("DSC-60" manufactured by Shimadzu Corporation) in accordance with JIS (Japanese Industrial Standards) K7121-2012.

[0144] The glass transition temperature measurements of resins (A1) to (A6) and (B1) to (B9) are shown in Tables 2 and 3. Resins (A1) to (A6) and (B1) to (B9) did not have a clear melting peak in the endothermic curve, and did not have a clear melting point. Resins (A1) to (A6) and (B1) to (B9) all had glass transition temperatures but did not have a clear melting point, and were therefore determined to be amorphous polyester resins.

[0145] On the other hand, the glass transition point of resin (B10) was 45° C. and the melting point was 130° C. Since resin (B10) has a glass transition point and a melting point, it was determined that resin (B10) is a crystalline polyester resin.

[0146] <Measurement of acid value and hydroxyl value> The acid value and hydroxyl value of resins (A1) to (A6) and (B1) to (B9) were measured using an automatic titration measuring device ("Automatic Titration Measuring Device COM-2500" manufactured by Hiranuma Sangyo Co., Ltd.) in accordance with JIS (Japanese Industrial Standards) K0070-1992.

[0147] The measurement results of the acid value and hydroxyl value of resins (A1) to (A6) and (B1) to (B9) are shown in Tables 2 and 3. Note that, since resin (B10) was confirmed to be a crystalline polyester resin and thus to be a resin related to a comparative example, the acid value and hydroxyl value were not measured.

[0148] [Preparation of colored resin] Next, colored resins (C1) to (C6) and (D1) to (D10) were prepared. The compositions of these colored resins are shown in Tables 4 and 5.

[0149] [Table 4]

[0150] [Table 5]

[0151] The meanings of the terms in Tables 4 and 5 are as follows. DB359: CI Disperse Blue 359. DB60: CI Disperse Blue 60. DR60:CI Disperse Red 60. DY54: CI Disperse Yellow 54. Amorphous: The resin in question is an amorphous polyester resin. Crystalline: The resin in question is a crystalline polyester resin.

[0152] <Preparation of Colored Resin (C1)> Resin (A1) (100 parts) and CI Disperse Blue 359 (10 parts) were mixed using an FM mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) to obtain a mixture. The mixture was kneaded using a twin-screw extruder (manufactured by Ikegai Corporation, "PCM-30") to obtain a kneaded colored resin (C1).

[0153] <Preparation of Colored Resins (C2) to (C6) and (D1) to (D10)> Colored resins (C2) to (C6) and (D1) to (D10) were each prepared in the same manner as colored resin (C1), except that the resins and disperse dyes shown in Tables 4 and 5 were used.

[0154] [Preparation of Composite Particle Dispersion] Next, composite particle dispersions (D-C1) to (D-C6) and (D-D1) to (D-D10) were prepared. The colored resins used in the preparation of these dispersions are shown in the "Colored Resin" column of Tables 6 and 7 described below.

[0155] <Preparation of Dispersion (D-C1)> A two-neck flask equipped with a stirrer and a thermocouple was charged with colored resin (C1) (100 g) and methyl ethyl ketone (100 g). The contents of the flask were heated to 70° C. to dissolve the colored resin in methyl ethyl ketone, and a solution was obtained. The obtained solution (40 g) and a neutralizing agent (1N aqueous sodium hydroxide solution, 5 g) were charged in another flask, and the carboxy group of the colored resin (C1) was ionized. A mixture of water (remaining amount) and methyl ethyl ketone (40 g) was added to the flask, and the contents of the flask were thoroughly stirred. The "remaining amount" is an amount such that the solid content concentration of the dispersion after the methyl ethyl ketone was distilled off under reduced pressure was 10% by mass. In this way, phase inversion emulsification was advanced, and composite particles, which are emulsified particles of the colored resin (C1), were formed. Next, methyl ethyl ketone was distilled off under reduced pressure from the contents of the flask at a temperature of 30° C. The distillation under reduced pressure yielded a dispersion (D-C1), which is an aqueous dispersion of the composite particles.

[0156] <Preparation of Dispersions (D-C2) to (D-C6), (D-D1) to (D-D5), and (D-D7) to (D-D10)> Each of the dispersions (D-C2) to (D-C6), (D-D1) to (D-D5), and (D-D7) to (D-D10) was prepared in the same manner as the dispersion (D-C1), except that the colored resins shown in Tables 6 to 7 were used and that the amounts of 1N aqueous sodium hydroxide solution shown in Tables 6 to 7 were added.

[0157] In addition, the colored resin is microparticulated by phase inversion emulsification to form composite particles. Therefore, for the composite particles contained in the dispersions (D-C1) to (D-C6), (D-D1) to (D-D5), and (D-D7) to (D-D10), the polyester resin ratio in the composite particles was calculated to be 91% by mass from the formula "(polyester resin ratio) = 100 x (mass of polyester resin) / [(mass of colored resin)] = 100 x (mass of polyester resin) / [(mass of polyester resin) + (mass of disperse dye)] = 100 x 100 / (100 + 10)".

[0158] <Attempt to prepare dispersion (D-D6)> An attempt was made to prepare dispersion (D-D6) in the same manner as dispersion (D-C1), except that the colored resin (D6) shown in Table 7 was used and the amount of 1N sodium hydroxide aqueous solution shown in Table 7 was added. However, the colored resin (D6) was dissolved in the aqueous phase during phase inversion emulsification, and phase inversion emulsification did not proceed. For this reason, composite particles, which are emulsified particles, could not be formed, and dispersion (D-D6) could not be prepared.

[0159] [Ink preparation] Next, inks (IA-1) to (IA-7), (IB-1) to (IB-5), and (IB-7) to (IB-11) were prepared. The compositions of these inks are shown in Tables 6 to 7 below. As already mentioned, since dispersion (D-D6) could not be prepared, ink (IB-6) was not prepared.

[0160] <Preparation of Ink (IA-1)> Dispersion (D-C1) (20.0 g, solid content concentration: 10% by mass), propylene glycol (4.0 g), glycerin (4.0 g), a surfactant ("Surfynol (registered trademark) 104PG-50" manufactured by Nissin Chemical Industry Co., Ltd., 0.1 g), and a crosslinking agent (blocked isocyanate, "Meikanate CX" manufactured by Meisei Chemical Industry Co., Ltd., 1.0 g) were stirred using a stirrer to obtain a mixed liquid. The mixed liquid was filtered using a filter with a pore size of 5 μm to obtain an ink (IA-1).

[0161] <Preparation of Inks (IA-2) to (IA-7), (IB-1) to (IB-5), and (IB-7) to (IB-11)> Inks (IA-2) to (IA-7), (IB-1) to (IB-5), and (IB-7) to (IB-11) were each prepared in the same manner as ink (IA-1), except that the types of dispersions shown in Tables 6 to 7 were used, and the types and amounts of crosslinkers shown in Tables 6 to 7 were used.

[0162] <D of composite particles contained in ink 50 Measurements > D of composite particles contained in ink 50was measured using a dynamic light scattering particle size distribution analyzer (Malvern Zetasizer 1000) according to the method described in ISO 22412:2017. 50 are shown in Tables 6 and 7.

[0163] [evaluation] The following evaluations were carried out using each of the inks (IA-1) to (IA-7), (IB-1) to (IB-5), and (IB-7) to (IB-11) to be evaluated. As mentioned above, ink (IB-6) was not prepared, so ink (IB-6) was not evaluated.

[0164] <Evaluation of dispersibility> The ink was filtered using a membrane filter (pore size: 5 μm). The mass of solids remaining on the filter without passing through was measured. The solids remaining rate was calculated from the formula "(solids remaining rate)=100×(mass of solids remaining on the filter) / (mass of solids contained in the ink)". From the solids remaining rate, the dispersibility of the ink was evaluated according to the following criteria. Inks with a rating of A or B were judged to have good dispersibility, and inks with a rating of C were judged to have poor dispersibility. The evaluation results are shown in Tables 6 to 7.

[0165] (Evaluation Criteria for Dispersibility) Evaluation A: The residual solid content is 0% by mass or more and 5% by mass or less. Rating B: The residual solid content is more than 5% by mass and 10% by mass or less. Rating C: The residual solid content exceeds 10% by mass.

[0166] <Evaluation of storage stability> D of composite particles contained in ink 50 Measure the D before storage. 50 Next, 30 mL of ink was placed in a 50 mL container and the container was sealed. The container containing the sealed ink was placed in a thermostatic chamber set at 60° C. and left for one week. Next, the D 50 Measure the D after storage. 50In addition, before saving, 50 and D after storage 50 is the D of the composite particles contained in the ink 50 The measurement was performed in the same manner as in the measurement of particle size change after storage. 50 )-(D before saving 50 )] / (D before saving 50 )" The rate of change in particle diameter was calculated. The storage stability of the ink was evaluated from the rate of change in particle diameter according to the following criteria. The evaluation results are shown in Tables 6 to 7. Inks that received an evaluation of A or B were judged to have good storage stability, and inks that received an evaluation of C were judged to have poor storage stability. The evaluation results are shown in Tables 6 to 7.

[0167] (Evaluation criteria for storage stability) Grade A: The rate of change in particle size is less than 5%. Evaluation B: The rate of change in particle size is 5% or more and 10% or less. Grade C: The rate of change in particle size is more than 10%.

[0168] <Preparation of printed items for evaluation> Printed materials for evaluation, which will be used in the evaluation of image quality, evaluation of friction fastness, and evaluation of suppression of deterioration of tactile sensation, were prepared by the following method. An inkjet printing tool equipped with a recording head (Kyocera Corporation's inkjet print head "KJ4B") was used. Inks were filled into ink tanks corresponding to the colors of ink. The filled ink tanks were set in the tool. A solid image with an image density of 100% was printed on a polyester fabric (Tetlon Pongee fabric) as the printing target, using the inkjet printing tool. Next, the printing target was heated at 180°C for 60 seconds to dry the ink, and a printed material for evaluation was obtained.

[0169] <Image evaluation> The images printed on the evaluation printed textiles were observed with a loupe at 50x magnification and with the naked eye. The images were then checked for the presence or absence of image defects. Image defects were confirmed to include image streaks and uneven shading. Image streaks are caused by nozzle clogging and misaligned ink ejection from the nozzle. Based on the results of checking for the presence or absence of image defects, the images were evaluated according to the following criteria. Inks with a rating of 3 or more were judged to have good images, and inks with a rating of 2 or less were judged to have bad images. The evaluation results are shown in Tables 6 to 7.

[0170] (Image evaluation criteria) Evaluation 5: No image defects were observed either through a loupe or by naked eye observation. Rating 4: Some image defects are observed through a magnifying glass, but no image defects are observed through naked eye observation. Rating 3: Image defects are clearly visible when observed with a magnifying glass, but are not visible when observed with the naked eye. Rating 2: Image defects are clearly observed through a magnifying glass, and some image defects are observed through naked eye observation. Evaluation 1: Image defects are clearly observed both through a loupe and through the naked eye.

[0171] <Evaluation of friction fastness> According to the dry test and wet test of the friction tester type II (Gakushin type) method described in JIS L-0849:2013 (Test method for color fastness to friction), the solid image printed on the evaluation print was rubbed with a white cotton cloth for friction. The degree of coloring of the white cotton cloth for friction after rubbing was evaluated in accordance with the "criteria for judging discoloration" described in Clause 10 (Judgment of color fastness) of JIS L-0801:2011 (General rules for color fastness test method). The degree of coloring of the white cotton cloth for friction was judged on a 9-level scale (in order of increasing degree of contamination, 1st grade, 1-2nd grade, 2nd grade, 2-3rd grade, 3rd grade, 3-4th grade, 4th grade, 4-5th grade, and 5th grade). The judgment result of the above dry test was taken as the dry friction fastness, and the judgment result of the above wet test was taken as the wet friction fastness. The smaller the degree of coloring of the white cotton cloth for friction (closer to grade 5), the better the friction fastness. The dry friction fastness and wet friction fastness were evaluated based on the degree of coloring of the white cotton friction cloth after the friction test, according to the following criteria. The evaluation results are shown in Tables 6 to 7.

[0172] (Evaluation criteria for dry friction fastness) Good: Dry friction fastness is grade 4 or higher. Poor: Dry friction fastness is less than grade 4.

[0173] (Evaluation criteria for wet friction fastness) Good: Wet friction fastness is grade 3 or higher. Poor: Wet friction fastness is less than grade 3.

[0174] <Evaluation of prevention of deterioration of tactile sensation> By touching the printed fabric for evaluation with hands, the three items of stiffness, sliminess, and difficulty in swelling of the printed fabric for evaluation were evaluated on a three-level scale of A (good), B (average), and C (bad). The less the stiffness of the printed fabric for evaluation was reduced, the better the item of stiffness was evaluated. The less the sliminess of the printed fabric for evaluation was reduced, the better the item of sliminess was evaluated. The less the swelling of the printed fabric for evaluation was reduced, the better the item of difficulty in swelling was evaluated. Then, according to the following criteria, it was evaluated whether the deterioration of the tactile feel of the printed fabric for evaluation was suppressed. Inks with a rating of 3 or more were judged to have the deterioration of the tactile feel of the printed fabric suppressed, and inks with a rating of 2 or less were judged to have the deterioration of the tactile feel of the printed fabric not suppressed. The evaluation results are shown in Tables 6 to 7.

[0175] (Evaluation criteria for preventing deterioration of tactile sensation) Rating 5: There are three A ratings in the three evaluation items. Rating 4: There are two A's in the three evaluation categories. There are no C's in the three evaluation categories. Rating 3: There is one A rating in the three evaluation items. There are no C ratings in the three evaluation items. Grade 2: There are no A's in the three evaluation items. There are one or two C's in the three evaluation items. Rating 1: There are no A's in the three evaluation items. There are three C's in the three evaluation items.

[0176] [Table 6]

[0177] [Table 7]

[0178] The meanings of the terms in Tables 6 and 7 are as follows. Dispersion: A dispersion containing the composite particles. Colored resin: the colored resin used to form the composite particles contained in the dispersion. Amount of NaOH: mass (unit: g) of the 1N aqueous sodium hydroxide solution added in the above [Preparation of Composite Particle Dispersion]. D 50 : D of composite particles contained in ink 50 . CX: Blocked isocyanate ("Meikanate CX" manufactured by Meisei Chemical Industry Co., Ltd.). SU: Blocked isocyanate ("SU-268A" manufactured by Meisei Chemical Industry Co., Ltd.). Dry friction: Evaluation of dry friction fastness. Wet rubbing: Evaluation of wet rubbing fastness. Touch: Evaluation of suppression of decline in touch sensation. -: Ink preparation, measurement, and evaluation were not performed because composite particles could not be formed.

[0179] As shown in Table 3, the glass transition point of resin (B1) was less than 45° C. As shown in Table 5, resin (B1) was used to prepare colored resin (D1), and as shown in Table 7, colored resin (D1) was used to prepare dispersion (D-D1), and ink (IB-1) was used to prepare dispersion (D-D1). As shown in Table 7, the evaluation results of storage stability and dry rub fastness of ink (IB-1) were both poor.

[0180] As shown in Table 3, the acid value of resin (B2) was less than 10 mgKOH / g, and the hydroxyl value was less than 20 mgKOH / g. As shown in Table 5, resin (B2) was used to prepare colored resin (D2), and as shown in Table 7, colored resin (D2) was used to prepare dispersion (D-D2), and ink (IB-2) was used to prepare dispersion (D-D2). As shown in Table 7, the evaluation results of the dispersibility and image of ink (IB-2) were both poor.

[0181] As shown in Table 3, the glass transition point of resin (B3) was above 75° C. As shown in Table 5, resin (B3) was used to prepare colored resin (D3), and as shown in Table 7, colored resin (D3) was used to prepare dispersion (D-D3), and ink (IB-3) was prepared using dispersion (D-D3). As shown in Table 7, the evaluation results of dry rub fastness and inhibition of deterioration in tactile sensation of ink (IB-3) were both poor.

[0182] As shown in Table 3, the acid value of resin (B4) was more than 70 mgKOH / g. As shown in Table 5, resin (B4) was used to prepare colored resin (D4), as shown in Table 7, colored resin (D4) was used to prepare dispersion (D-D4), and dispersion (D-D4) was used to prepare ink (IB-4). As shown in Table 7, the evaluation result of wet rub fastness of ink (IB-4) was poor.

[0183] As shown in Table 3, the hydroxyl value of resin (B5) exceeded 60 mgKOH / g. As shown in Table 5, resin (B5) was used to prepare colored resin (D5), and as shown in Table 7, colored resin (D5) was used to prepare dispersion (D-D5), and ink (IB-5) was used to prepare dispersion (D-D5). As shown in Table 7, the evaluation results of wet rub fastness and inhibition of deterioration of tactile sensation of ink (IB-5) were both poor.

[0184] As shown in Table 5, the resin (B6) was used to prepare the colored resin (D6). However, as shown in Table 7, the colored resin (D6) could not be used to form composite particles. Specifically, the colored resin (D6) was dissolved in the aqueous phase during phase inversion emulsification, and the phase inversion emulsification did not proceed, so that composite particles, which are emulsified particles, could not be formed. As a result, the dispersion (D-D6) and, in turn, the ink (IB-6) could not be prepared. As shown in Table 7, the ink (IB-6) could not be evaluated. The ink (IB-6) that was attempted to be prepared was outside the scope of the present invention in that it was unable to form composite particles and did not contain composite particles.

[0185] As shown in Table 7, the ink (IB-7) did not contain a crosslinking agent. As shown in Table 7, the evaluation results of the dry rub fastness and wet rub fastness of the ink (IB-7) were both poor.

[0186] As shown in Table 3, the hydroxyl value of resin (B7) was less than 20 mgKOH / g. As shown in Table 5, resin (B7) was used to prepare colored resin (D7), as shown in Table 7, colored resin (D7) was used to prepare dispersion (D-D7), and ink (IB-8) was prepared using dispersion (D-D7). As shown in Table 7, the evaluation results of the dispersibility and image of ink (IB-8) were both poor.

[0187] As shown in Table 3, the acid value of resin (B8) was less than 10 mgKOH / g. As shown in Table 5, resin (B8) was used to prepare colored resin (D8), and as shown in Table 7, colored resin (D8) was used to prepare dispersion (D-D8), and ink (IB-9) was prepared using dispersion (D-D8). As shown in Table 7, the evaluation results of dispersibility, storage stability, and image of ink (IB-9) were all poor.

[0188] As shown in Table 3, the glass transition point of resin (B9) was less than 45° C., the acid value was less than 10 mgKOH / g, and the hydroxyl value was less than 20 mgKOH / g. As shown in Table 5, resin (B9) was used to prepare colored resin (D9), and as shown in Table 7, colored resin (D9) was used to prepare dispersion (D-D9), and ink (IB-10) was used to prepare dispersion (D-D9). As shown in Table 7, the evaluation results of dispersibility, storage stability, and image of ink (IB-10) were all poor.

[0189] As shown in Table 5, resin (B10) was not a non-crystalline polyester resin. As shown in Table 5, resin (B10) was used to prepare colored resin (D10), and as shown in Table 7, colored resin (D10) was used to prepare dispersion (D-D10), and ink (IB-11) was prepared using dispersion (D-D10). As shown in Table 7, the evaluation results of dispersibility, storage stability, image, and dry rub fastness of ink (IB-11) were poor.

[0190] On the other hand, the inks (IA-1) to (IA-7) each had the following composition. That is, these inks contained an aqueous medium, composite particles, and a crosslinking agent. As shown in Table 4, the polyester resins contained in the composite particles (more specifically, resins (A1) to (A6)) were non-crystalline. As shown in Table 2, the glass transition points of the polyester resins (more specifically, resins (A1) to (A6)) were 45° C. or higher and 75° C. or lower, the acid values ​​were 10 mgKOH / g or higher and 70 mgKOH / g or lower, and the hydroxyl values ​​were 20 mgKOH / g or higher and 60 mgKOH / g or lower. As shown in Table 7, the crosslinking agents contained in these inks included blocked isocyanates (more specifically, Meikanate CX or SU-268A). As shown in Table 6, the evaluation results of the dispersibility, storage stability, image, dry rub fastness, wet rub fastness, and suppression of deterioration in the tactile feel of the inks (IA-1) to (IA-7) were all good.

[0191] From the above, it has been shown that the inks according to the present invention, including inks (IA-1) to (IA-7), and the inks produced by the production method according to the present invention, have excellent dispersibility and storage stability, can print images with few image defects and excellent friction fastness, and can suppress deterioration in the tactile feel of the printed textile. Furthermore, it is considered that the inkjet textile printing method according to the present invention using such inks can suppress ink aggregation by using inks with excellent dispersibility and storage stability, can print images with few image defects and excellent friction fastness, and can suppress deterioration in the tactile feel of the printed textile. [Industrial Applicability]

[0192] The ink according to the present invention can be used, for example, to print an image on a printing target such as fabric using an inkjet printing device. [Explanation of symbols]

[0193] 10: Inkjet printing device 11: Payout section 12: Ink ejection section 13: Recording head 14:Drying section 15: Heat treatment section 16a: Heating roller 16b: Pressure roller 17: Recovery Department P1: Printing target P2: Textile printing

Claims

1. The composition includes an aqueous medium, composite particles, and a crosslinking agent, The composite particles are emulsion particles of a composite in which a polyester resin and a disperse dye are mixed, The polyester resin has a repeating unit derived from a polyhydric alcohol and a repeating unit derived from a polycarboxylic acid, The polyester resin is non-crystalline, The glass transition point of the polyester resin is 45° C. or higher and 75° C. or lower, The acid value of the polyester resin is 10 mgKOH / g or more and 70 mgKOH / g or less, The hydroxyl value of the polyester resin is 20 mgKOH / g or more and 60 mgKOH / g or less, The crosslinking agent comprises a blocked isocyanate, The composite particles have a volume median diameter of 85 nm or more and 180 nm or less.

2. The repeating unit derived from the polyhydric alcohol includes at least a first repeating unit derived from a trihydric or higher alcohol, 2. The ink-jet ink according to claim 1, wherein a content of the first repeating unit in the total amount of the repeating units derived from the polyhydric alcohol is 0.5 mol % or more and 10.0 mol % or less.

3. The repeating unit derived from the polyhydric alcohol includes at least a second repeating unit derived from ethylene glycol, 3. The ink-jet ink according to claim 1, wherein a content of the second repeating unit in the total amount of the repeating units derived from the polyhydric alcohol is 50.0 mol % or more and 90.0 mol % or less.

4. The repeating unit derived from the polyvalent carboxylic acid includes at least a third repeating unit derived from a trivalent or higher carboxylic acid, 4. The ink-jet ink according to claim 1, wherein a content of the third repeating unit in the total amount of the repeating units derived from the polyvalent carboxylic acid is 0.5 mol % or more and 9.0 mol % or less.

5. 5. The ink-jet ink according to claim 1, wherein the repeating units derived from the polycarboxylic acid include at least a fourth repeating unit derived from a polycarboxylic acid having a sulfonic acid group, and a content of the fourth repeating unit in a total amount of the repeating units derived from the polycarboxylic acid is greater than 0.0 mol % and is 15.0 mol % or less, or the repeating units derived from the polycarboxylic acid do not include the fourth repeating unit.

6. the repeating unit derived from a polycarboxylic acid includes at least a fifth repeating unit derived from a polycarboxylic acid having an aromatic hydrocarbon, the repeating unit derived from a polyhydric alcohol includes at least a sixth repeating unit derived from a polyhydric alcohol having an aromatic hydrocarbon, 6. The ink-jet ink according to claim 1, wherein a total content of the fifth repeating unit and the sixth repeating unit in a total amount of the repeating unit derived from the polyvalent carboxylic acid and the repeating unit derived from the polyhydric alcohol is 50 mol % or more.

7. The ink-jet ink according to any one of claims 1 to 6, wherein the content of the polyester resin in the composite particles is 50% by mass or more and less than 100% by mass.

8. The ink-jet ink according to any one of claims 1 to 7, further comprising a neutralizing agent.

9. The method includes a step of ejecting ink from a recording head onto a printing target, The ink-jet printing method according to any one of claims 1 to 8, wherein the ink is an ink-jet ink.

10. The method further includes a heating step of heating the ink that has landed on the printing target, The subject to be printed has a hydroxy group, The ink-jet printing method according to claim 9 , wherein the ink is heated to crosslink the hydroxyl groups of the object to be printed with the hydroxyl groups of the polyester resin contained in the composite particles by the crosslinking agent.

11. a kneading step of kneading the polyester resin and the disperse dye to obtain a kneaded mixture; a composite particle forming step of forming the composite particles by phase inversion emulsification of an oil phase containing the kneaded mixture and an organic solvent and an aqueous phase containing water; a mixing step of mixing the composite particles, the aqueous medium, and the crosslinking agent to obtain an ink, The ink-jet ink according to any one of claims 1 to 8, wherein the ink is an ink-jet ink.

12. The method for producing an inkjet ink according to claim 11 , wherein in the composite particle forming step, a neutralizing agent is added to the oil phase to ionize a carboxy group of the polyester resin contained in the kneaded product.

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