Inkjet composition and inkjet recording method

Abstract

To provide an inkjet composition which is suitably usable to manufacture a recorded matter having a recording part that is excellent in discharge stability by an inkjet method and is excellent in color development property, and an inkjet recording method which can stably discharge droplets by the inkjet method, and is suitably adoptable to manufacture the recorded matter having the recording part excellent in color development property.SOLUTION: An inkjet composition contains water, a polyester resin having a sulfo group, and a coloring material, wherein the coloring material is contained in particles composed of a material containing the polyester resin, an average particle size of the particles is 100 nm or less, and a percentage content of the particles in the inkjet composition is 15 mass% or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an inkjet composition and an inkjet recording method. [Background technology]

[0002] In recent years, the applications of inkjet printing have expanded, and inkjet printing is now used not only in office and home printing machines but also in commercial printing, textile printing, and the like.

[0003] In addition, inkjet printing has come to be applied to a variety of recording media, including fabrics, films, cardboard, and the like, in addition to paper.

[0004] While the use of water-based inks is desirable from the standpoint of ease of use and safety, it is difficult to obtain a coating film with sufficient strength using water-based inks. For this reason, inkjet inks containing resin materials are used, but when ordinary polyesters or the like are used, there is a problem in that the ejection stability when using the inkjet method decreases.

[0005] In order to solve such problems, an inkjet ink containing a polyester resin having a highly hydrophilic sulfo group has been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-158645 Summary of the Invention [Problem to be solved by the invention]

[0007] Although the use of such inkjet inks can improve the ejection stability when using an inkjet method, there is a problem in that color development is reduced. When the solid content is increased to improve color development, there is a problem in that the ejection stability when using an inkjet method is reduced.

[0008] That is, there is a problem in that it is not possible to achieve both ejection stability by the ink jet method and color development properties. [Means for solving the problem]

[0009] The present invention has been made to solve the above-mentioned problems, and can be realized as the following application examples.

[0010] The composition for inkjet according to the application example of the present invention comprises: A composition for inkjet use that is applied to a fabric, A composition containing water, a polyester resin having a sulfo group, and a coloring material. fruit , the colorant is contained in particles made of a material containing the polyester resin, the coloring material includes at least one selected from the group consisting of sublimation dyes, oil-based dyes, and disperse dyes; The particles have an average particle size of 100 nm or less, and the content of the particles in the composition for inkjet is 15% by mass or more.

[0011] Furthermore, the composition for inkjet according to another application example of the present invention has a viscosity at 25° C. of 9.0 mPa·s or less.

[0013] In the composition for inkjet according to another application example of the present invention, the amount of sulfur atoms contained in the polyester resin is 0.60 at % or less.

[0014] In a composition for inkjet according to another application example of the present invention, the particles contain a plurality of types of polyester resins having different sulfo group contents.

[0015] An inkjet recording method according to an application example of the present invention includes a discharge step of discharging the inkjet composition of the present invention by an inkjet method.

[0016] In addition, in the inkjet recording method according to another application example of the present invention, after the ejection step, The fabric The method further includes a heating step of heating the

[0017] In addition, in the ink jet recording method according to another application example of the present invention, fabric The heating temperature is 100°C or higher and 160°C or lower. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic perspective view of a recording apparatus according to a preferred embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Preferred embodiments of the present invention will be described in detail below. <1> Inkjet composition

[0020] The inkjet composition of the present invention contains water, a polyester resin having a sulfo group, and a colorant. The colorant is contained in particles made of a material containing the polyester resin, and the particles have an average particle size of 100 nm or less and a content of the particles in the inkjet composition of 15 mass % or more.

[0021] By satisfying these conditions, the inkjet composition can have excellent ejection stability when used in an inkjet method, and can also have excellent color development in the recorded portion. In particular, excellent color development can be achieved on various recording media. Furthermore, the inkjet composition can have excellent fixability and adhesion strength in the recorded portion. Furthermore, the inkjet composition of the present invention can be applied to a method for producing a recorded material that does not include a transfer step, as will be described in detail later, and is preferable from the viewpoints of improving the productivity of recorded materials, reducing the production costs of recorded materials, and saving resources.

[0022] The reason why such excellent effects are obtained is considered to be as follows. That is, when the polyester resin constituting the particles has a sulfo group and a sufficiently small average particle size, the hydrophilicity of the particles can be improved, and the fluidity of the particles in the inkjet composition can be improved. As a result, the dispersion stability of the particles in the inkjet composition and the ejection stability of the inkjet composition by the inkjet method can be improved. Furthermore, when the polyester resin constituting the particles contained in the inkjet composition has a sulfo group and a sufficiently small average particle size, the above-mentioned effects can be obtained, and therefore the ejection stability of the inkjet composition can be improved sufficiently even when the particle content in the inkjet composition is high as described above. Therefore, it is believed that the solid content in the inkjet composition can be sufficiently increased, thereby achieving both ejection stability by the inkjet method and color development of the recorded portion by the inkjet composition. Furthermore, when the average particle size of the particles is sufficiently small as described above, the proportion of particles contained in the region near the surface of the particles can be increased, and the color development of the recorded portion formed using the inkjet composition can be improved particularly.

[0023] Furthermore, the colorant is applied to the recording medium in a state in which the resin material has been suitably colored, which allows the fixation of the recorded portion in the produced recorded matter to be excellent, and the colorant can be suitably prevented from unintentionally falling off the recorded matter, etc., and the colorant can be stably retained in the recorded matter. Therefore, even when the recorded matter is subjected to heat treatments such as washing / cleaning with hot water, heat drying in a dryer, ironing, etc., the colorant can be effectively prevented from unintentionally diffusing outside the recorded matter, and the durability of the recorded matter can be particularly excellent. Furthermore, when a dye is contained as the coloring material, the above-mentioned effects are even more pronounced.

[0024] On the other hand, if the above conditions are not met, satisfactory results will not be obtained. For example, if the composition does not contain a polyester resin having a sulfo group, the hydrophilicity of the particles contained in the composition for inkjet cannot be sufficiently increased, and the ejection stability of the composition for inkjet by the inkjet method decreases.

[0025] Furthermore, if the average particle size of the particles is too large, the ejection stability of the inkjet composition when used in an inkjet method will decrease. Furthermore, although a highly hydrophobic colorant in the particles generally tends to be concentrated near the center so as to be away from water, if the average particle size of the particles is too large, the colorant will be concentrated near the center, which is farther from the surface of the particles, and the color development of the recording portion formed using the inkjet composition will decrease even if the same amount of colorant is contained.

[0026] As described above, the average particle size of the particles contained in the inkjet composition of the present invention may be 100 nm or less, preferably 90 nm or less, more preferably 85 nm or less, and even more preferably 80 nm or less. The lower limit of the average particle size of the particles is preferably 5 nm, more preferably 20 nm, and even more preferably 30 nm. This makes the above-mentioned effects more pronounced.

[0027] In this specification, unless otherwise specified, the average particle size means the particle size at which the frequency of particles reaches 50% when the particle amount is cumulatively calculated from the small particle size side in the particle distribution measured by dynamic light scattering, and can be determined, for example, by measurement using a zeta potential / particle size measurement system "ELSZ-1000ZS" (manufactured by Otsuka Electronics Co., Ltd.).

[0028] As described above, the content of the particles in the composition for inkjet of the present invention may be 15% by mass or more, preferably 18% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. The upper limit of the content of the particles in the composition for inkjet of the present invention is preferably 45% by mass, more preferably 40% by mass, and even more preferably 35% by mass. This makes the above-mentioned effects more pronounced.

[0029] In this specification, the term "inkjet composition" refers to the ink itself to be ejected by the inkjet method, as well as the stock solution used to prepare the ink. In other words, the inkjet composition of the present invention may be ejected by the inkjet method as is, or may be ejected by the inkjet method after being diluted or otherwise treated. Examples of inkjet methods include on-demand methods such as a charge deflection method, a continuous method, a piezoelectric method, and a bubble jet (registered trademark) method.

[0030] <1-1>Water The ink-jet composition of the present invention contains water, which mainly has the function of imparting fluidity to the ink-jet composition, for example, by functioning as a dispersion medium for particles. As the water, for example, pure water such as RO water, distilled water, or ion-exchanged water may be used.

[0031] The lower limit of the water content in the inkjet composition is not particularly limited, but is preferably 30.0 mass%, more preferably 35.0 mass%, and even more preferably 40.0 mass%. The upper limit of the water content in the inkjet composition is not particularly limited, but is preferably 75.0 mass%, more preferably 70.0 mass%, and even more preferably 65.0 mass%.

[0032] This makes it possible to more reliably adjust the viscosity of the composition for inkjet to a suitable value. Furthermore, the dispersion stability of the particles in the composition for inkjet can be improved. Therefore, the ejection stability of the composition for inkjet by the inkjet method can be improved.

[0033] <1-2> Coloring materials The inkjet composition of the present invention contains a coloring material, which is a component that colors a recording medium and has a significant effect on the appearance of the recorded matter.

[0034] Examples of coloring materials include various pigments such as organic pigments and inorganic pigments, and various dyes, and one or more selected from these may be used in combination.

[0035] Examples of organic pigments include azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene and perylene pigments, anthraquinone pigments, quinacridone pigments, dioxandine pigments, thioindigo pigments, isoindolinone pigments, and quinophthaloni pigments; dye lakes such as basic dye lakes and acid dye lakes; nitro pigments, nitroso pigments, aniline black, and daylight fluorescent pigments.

[0036] Examples of inorganic pigments include titanium oxide, iron oxide, carbon black, etc. Carbon black that can be used includes those produced by known methods such as the contact method, furnace method, and thermal method.

[0037] Examples of dyes include sublimation dyes, oil dyes, disperse dyes, fluorescent dyes, reactive dyes, acid dyes, sulfur dyes, vat dyes, and cationic dyes.

[0038] Among these, it is preferable that the coloring material contains at least one selected from the group consisting of sublimation dyes, oil-based dyes, and disperse dyes.

[0039] This allows the particles to be colored more suitably, and the color development of the recording portion formed using the inkjet composition can be improved.

[0040] Examples of disperse dyes and sublimation dyes include CI Disperse Yellow 1, 3, 4, 5, 7, 9, 13, 23, 24, 30, 33, 34, 42, 44, 49, 50, 51, 54, 56, 58, 60, 61, 63, 64, 66, 68, 71, 74, 76, 79, 82, 83, 85, 86, 88, 90, 91, 93, 98, 99, 100, 104, 108, 114, 116, 118, 119, 122, 124, 126, 135, 140, 141, 149, 154, 160, 162, 163, 164, 165, 179, 180, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 2 6, 192, 198, 199, 201, 202, 204, 210, 211, 215, 216, 218, 224, 227, 231, 232; CI Disperse Orange 1, 3, 5, 7, 11, 13, 17, 20, 21, 25, 29, 30, 31, 32, 33, 37, 38, 42, 43, 44, 45, 46, 47, 48, 49, 50, 53, 54, 55, 56, 57, 58, 59, 60, 61, 66, 71, 73, 76, 78, 80, 89, 90, 91, 93, 96, 97, 119, 127, 130, 139, 142; CI Disperse Red 1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 54, 55, 56, 58, 59, 60, 65, 72, 73, 74, 75, 76, 78, 81, 82, 86, 88, 90, 91, 92, 93, 96, 103, 105, 106, 107, 108, 110, 111, 113, 117, 118, 121, 122, 126, 127, 128, 131, 132, 134, 135, 137, 143, 145, 146, 151, 152, 153, 154, 157, 159, 164, 167, 169, 177, 179, 181, 183, 184, 185, 188, 189, 190, 191, 192, 200, 201, 202, 203, 205, 206, 207, 210, 221, 224, 225, 227, 229, 239, 240, 257, 258, 277, 278, 279, 281, 288, 298, 302, 303, 310, 311, 312, 320, 324, 328, 364; CI Disperse Violet 1, 4, 8, 23, 26, 27, 28, 31, 33, 35, 36, 38, 40, 43, 46, 48, 50, 51, 52, 56, 57, 59, 61, 63, 69, 77; CIDisperse Green 9; CI Disperse Brown 1, 2, 4, 9, 13, 19; CI Disperse Blue 3, 7, 9, 14, 16, 19, 20, 24, 26, 27, 35, 43, 44, 54, 55, 56, 58, 60, 62, 64, 71, 72, 73, 75, 79, 81, 82, 83, 87, 91, 92, 93, 94, 95, 96, 102, 106, 108, 112, 113, 115, 118, 120, 122, 125, 128, 130, 139, 141, 142, 143 146, 148, 149, 153, 154, 158, 165, 167, 171, 173, 174, 176, 181, 183, 185, 186, 187, 189, 197, 198, 200, 201, 205, 207, 211, 214, 224, 225, 257, 259, 267, 268, 270, 284, 285, 287, 288, 291, 293, 295, 297, 301, 315, 330, 333, 359, 360; CI Disperse Black 1, 3, 10, 24, etc.

[0041] Examples of oil-based dyes include CI Solvent Black 3, 7, 27, 29, and 34; CI Solvent Yellow 14, 16, 19, 29, 56, and 82; CI Solvent Red 1, 3, 8, 18, 24, 27, 43, 51, 72, 73, 132, and 218; CI Solvent Violet 3; CI Solvent Blue 2, 5, 11, and 70; CI Solvent Green 3 and 7; and CI Solvent Orange 2.

[0042] Examples of fluorescent dyes include CI Disperse Red 364, CI Disperse Red 362, CI Vat Red 41, CI Disperse Yellow 232, CI Disperse Yellow 184, CI Disperse Yellow 82, and CI Disperse Yellow 43.

[0043] Examples of reactive dyes include yellow dyes such as CI Reactive Yellow 2, 3, 18, 81, 84, 85, 95, 99, and 102; orange dyes such as CI Reactive Orange 5, 9, 12, 13, 35, 45, and 99; brown dyes such as CI Reactive Brown 2, 8, 9, 17, and 33; and CI Reactive Red 1, 3, 4, 13, 15, 24, 29, 31, 33, 120, 125, 151, 206, 218, and 226. , 245, etc.; violet dyes such as CI Reactive Violet 24; blue dyes such as CI Reactive Blue 2, 5, 10, 13, 14, 15, 15:1, 21, 49, 63, 71, 72, 75, 162, 176, CI Reactive Blue 4, 19, 198, etc.; green dyes such as CI Reactive Green 5, 8, 19, etc.; and black dyes such as CI Reactive Black 1, 8, 23, 39, etc.

[0044] The lower limit of the content of the colorant in the composition for inkjet is preferably 0.1% by mass, more preferably 0.2% by mass, and even more preferably 0.3% by mass, and the upper limit of the content of the colorant in the composition for inkjet is preferably 10.0% by mass, more preferably 7.0% by mass, and even more preferably 5.0% by mass.

[0045] This makes it possible to improve the color development and optical density of the recorded portion of a recorded material produced using the inkjet composition, and also to more effectively prevent the occurrence of undesired color unevenness in the recorded material.

[0046] It is sufficient that at least a portion of the coloring material constituting the inkjet composition is contained in the particles, and the inkjet composition may contain coloring material that is not contained in the particles.

[0047] However, the proportion of the colorant not contained in the particles relative to the total colorant contained in the inkjet composition is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

[0048] <1-3> Polyester resin containing sulfo groups The inkjet composition of the present invention contains a polyester resin having a sulfo group in the molecule. Hereinafter, such a polyester resin having a sulfo group in the molecule will also be referred to as a "sulfo group-containing polyester resin." The sulfo group-containing polyester resin has the function of improving the fixability and fastness of the recorded area in a recorded matter produced using the inkjet composition, as well as the function of improving the texture and feel. It also has the function of enhancing the color development of a colorant. Furthermore, due to its excellent hydrophilicity, the sulfo group-containing polyester resin has the function of increasing the dispersion stability of solid matter in an inkjet composition containing water, and as a result, it also has the function of improving the ejection stability of the inkjet composition.

[0049] Polyester is a general term for polymeric materials that have ester bonds in their main chains, and generally contains a chemical structure formed by dehydration condensation of a polyol component that has multiple hydroxyl groups in its molecule and a polycarboxylic acid component that has multiple carboxyl groups in its molecule.

[0050] The sulfo group-containing polyester resin preferably has a sulfo group and contains a diol component and a dicarboxylic acid component. The sulfo group-containing polyester resin may contain a trivalent or higher polyhydric alcohol component and a trivalent or higher polycarboxylic acid component in addition to the diol component and the dicarboxylic acid component.

[0051] The sulfo group may be contained in any site in the sulfo group-containing polyester resin, for example, in the diol component, the dicarboxylic acid component, or a site other than these, but is preferably contained in the dicarboxylic acid component. In other words, the sulfo group-containing polyester resin preferably contains a dicarboxylic acid component with a sulfonated chemical structure.

[0052] <1-3-1> Diol component Examples of diol components constituting the sulfo group-containing polyester resin include aliphatic diols such as 1,3-propanediol, methylpropanediol, neopentyl glycol, methylethylpropanediol, diethylpropanediol, butylethylpropanediol, ethylene glycol, 1,2-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and cyclohexanedimethanol, as well as compounds in which sulfo groups have been introduced into these diols. One or a combination of two or more selected from these can be used.

[0053] <1-3-2> Dicarboxylic acid component The dicarboxylic acid component constituting the sulfo group-containing polyester resin may have two or more carboxyl groups in the molecule.

[0054] The sulfo group-containing polyester resin may contain only one type of component as the dicarboxylic acid component, but preferably contains a plurality of types of components.

[0055] This enhances the amorphousness of the sulfo group-containing polyester resin, making it possible to suitably prevent crystallization and the like in the inkjet composition and in the recording part formed using the inkjet composition, thereby improving the storage stability of the inkjet composition and the reliability of the recorded matter. In particular, when an aromatic dicarboxylic acid as described below is contained as the dicarboxylic acid component, the above-mentioned crystallization is generally likely to occur, but by containing multiple types of dicarboxylic acid components in the sulfo group-containing polyester resin, it is possible to effectively prevent crystallization while enjoying the benefits of using an aromatic dicarboxylic acid as described below.

[0056] The dicarboxylic acid component constituting the sulfo group-containing polyester resin may be an aliphatic dicarboxylic acid, but preferably contains at least an aromatic dicarboxylic acid.

[0057] This can increase the resin strength. Furthermore, for example, the hydrophobicity of the sulfo group-containing polyester resin can be appropriately increased, and even when the inkjet composition is stored in a high-temperature environment, the sulfo group-containing polyester resin can be more effectively prevented from unintentionally dissolving in a dispersion medium whose main component is water. Furthermore, the water resistance of recorded matter produced using the inkjet composition can be improved. Furthermore, when the inkjet composition contains a dye as a colorant, the affinity between the sulfo group-containing polyester resin and the colorant can be improved, resulting in particularly excellent color development. Furthermore, the colorant can be suitably contained in the particles, and the effects described above can be more significantly exhibited.

[0058] Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenic acid, and other aromatic dicarboxylic acids, as well as compounds in which a sulfo group has been introduced into these. Among these, terephthalic acid, isophthalic acid, and compounds in which a sulfo group has been introduced into these are preferred.

[0059] The lower limit of the proportion of aromatic dicarboxylic acid in all dicarboxylic acid components constituting the sulfo group-containing polyester resin is preferably 0.4 mol%, more preferably 1.0 mol%, and even more preferably 1.4 mol%, and the upper limit of the proportion of aromatic dicarboxylic acid in all dicarboxylic acid components constituting the sulfo group-containing polyester resin is preferably 20.0 mol%, more preferably 15.0 mol%, and even more preferably 10.0 mol%.

[0060] This makes it possible to make the hydrophilicity of the particles more appropriate, thereby improving the dispersion stability of the particles in the composition for inkjet, the storage stability of the composition for inkjet, and the color development in the recorded portion of a recorded matter produced using the composition for inkjet.Furthermore, it is possible to improve the water resistance, oil resistance, etc. of a recorded matter produced using the composition for inkjet.

[0061] Examples of the aliphatic dicarboxylic acid include aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid, as well as fumaric acid, maleic acid, itaconic acid, hexahydrophthalic acid, tetrahydrophthalic acid, and cyclohexanedicarboxylic acid, and compounds in which a sulfo group has been introduced into these.

[0062] When the sulfo group-containing polyester resin contains multiple types of dicarboxylic acid components, the dicarboxylic acids preferably include terephthalic acid, isophthalic acid, and a compound in which a sulfo group has been introduced into terephthalic acid and / or isophthalic acid.

[0063] This provides the effect that although they are different, they have similar structures, making them more compatible and increasing the amorphousness.

[0064] The sulfo group-containing polyester resin may be one in which the distribution of sulfo groups within the molecule is uniform or non-uniform.

[0065] The polyester resin can be suitably synthesized by, for example, heating a mixture containing an ester compound of a diol component and a dicarboxylic acid component, and further containing components such as a catalyst as necessary. Suitable examples of the ester compound of the dicarboxylic acid component include methyl ester and ethyl ester. In the method for producing such a polyester resin, a sulfo group-containing polyester resin can be produced by using a component containing a sulfo group as part of the monomer components.

[0066] A sulfo-containing polyester resin having a non-uniform distribution of sulfo groups within the molecule can be suitably synthesized by a method including a first reaction step in which a mixture containing a diol component and an ester compound of a dicarboxylic acid component, and optionally a catalyst and other components, is heated, followed by a second reaction step in which a sulfo-containing monomer component is added to the reaction system and heated. By using a dicarboxylic acid component that is not an ester compound as the sulfo-containing monomer component, the distribution of sulfo groups within the molecule can be made more suitable.

[0067] The particles constituting the inkjet composition may contain at least one type of sulfo group-containing polyester resin, but preferably contain multiple types of sulfo group-containing polyester resins with different sulfo group contents.

[0068] This makes it easier to adjust the proportion of sulfo groups and the amount of sulfur atoms contained in the sulfo group-containing polyester resin. Furthermore, the distribution of sulfo groups in the particles can be more favorably achieved. Furthermore, by using a polyester resin with many sulfo groups in combination with a polyester resin with few sulfo groups that is highly hydrophobic and easily colored by colorants, it is possible to effectively suppress an increase in the viscosity of the inkjet composition while improving the color development of the recording area formed by the inkjet composition.

[0069] <1-3-3> Other ingredients The sulfo group-containing polyester resin may contain components other than the diol component and dicarboxylic acid component described above, such as a trivalent or higher polyhydric alcohol component, a trivalent or higher polycarboxylic acid component, a monocarboxylic acid component in which some of the hydroxyl groups of a diol component are esterified, or a monohydric alcohol component in which some of the carboxyl groups of a dicarboxylic acid component are esterified.

[0070] However, the content of components other than the diol component and the dicarboxylic acid component in the sulfo group-containing polyester resin is preferably 20.0% by mass or less, more preferably 10.0% by mass or less, and even more preferably 5.0% by mass or less.

[0071] <1-3-4> Other conditions The sulfo group-containing polyester resin preferably satisfies the following conditions.

[0072] The amount of sulfur atoms contained in the sulfo group-containing polyester resin is preferably 0.60 at% or less, more preferably 0.50 at% or less, and even more preferably 0.40 at% or less. The lower limit of the amount of sulfur atoms contained in the sulfo group-containing polyester resin is preferably 0.05 at%, more preferably 0.10 at%, and even more preferably 0.15 at%.

[0073] This makes it possible to easily adjust the viscosity of the inkjet composition to a more suitable value while preventing dissolution of the particles in the inkjet composition, and also makes it possible to improve the water resistance of the recording portion formed by the inkjet composition.

[0074] The amount of sulfur atoms contained in the sulfo group-containing polyester resin can be determined by energy dispersive X-ray spectroscopy (EDX). More specifically, the amount of sulfur atoms contained in the sulfo group-containing polyester resin can be determined, for example, by energy dispersive X-ray spectroscopy using C, N, O, Na, and S as the atoms to be measured. Energy dispersive X-ray analysis can be performed, for example, using a QUANTAX EDX system on a Hitachi TM3030 tabletop low-vacuum scanning electron microscope. The amount of sulfur atoms contained in the sulfo group-containing polyester resin shown in the examples below is also a value determined by the above-mentioned measurement.

[0075] In this specification, the degree of sulfonation of the sulfo group-containing polyester resin refers to the proportion of monomers having a sulfo group in all the monomers constituting the sulfo group-containing polyester resin.

[0076] The lower limit of the acid value of the sulfo group-containing polyester resin is preferably 1.0 KOHmg / g, more preferably 1.5 KOHmg / g, and even more preferably 2.0 KOHmg / g, and the upper limit of the acid value of the sulfo group-containing polyester resin is preferably 15.0 KOHmg / g, more preferably 10.0 KOHmg / g, and even more preferably 5.0 KOHmg / g.

[0077] The lower limit of the number average molecular weight of the sulfo group-containing polyester resin is preferably 1500, more preferably 3000, and even more preferably 10000. The upper limit of the number average molecular weight of the sulfo group-containing polyester resin is preferably 25000, more preferably 20000, and even more preferably 18000.

[0078] This makes it possible to achieve both higher levels of fixability of the sulfo group-containing polyester resin to recording media and higher levels of durability of recorded matter produced using the inkjet composition, and also makes it possible to improve the color development of coloring materials on various recording media.

[0079] The lower limit of the glass transition point of the sulfo group-containing polyester resin is preferably 0°C, more preferably 25°C, and even more preferably 40°C. The upper limit of the glass transition point of the sulfo group-containing polyester resin is preferably 90°C, more preferably 75°C, and even more preferably 70°C.

[0080] This makes it possible to achieve both ease of fixing of the sulfo group-containing polyester resin to a recording medium and durability of a recorded matter produced using the inkjet composition at a higher level.

[0081] The lower limit of the content of the sulfo group-containing polyester resin in the composition for inkjet is preferably 10.0% by mass, more preferably 14.0% by mass, and even more preferably 16.0% by mass, and the upper limit of the content of the sulfo group-containing polyester resin in the composition for inkjet is preferably 47.0% by mass, more preferably 45.0% by mass, and even more preferably 44.0% by mass.

[0082] The content of the coloring material in the inkjet composition is X D [mass %], the content of the sulfo group-containing polyester resin in the composition for inkjet is X P When expressed as [mass%], X P / X D The lower limit of X is preferably 4, more preferably 10, and even more preferably 15. P / X D The upper limit of is preferably 300, more preferably 200, and even more preferably 100.

[0083] This makes it possible to improve the color development of the recorded portion formed using the composition for inkjet, and also improve the fixability of the recorded portion to the recording medium, and more effectively prevent the coloring material from unintentionally diffusing to the outside of the recorded matter when the recorded matter produced using the composition for inkjet is subjected to heat treatment such as washing / cleaning with hot water, heat drying in a dryer, or ironing.

[0084] The sulfo group-containing polyester resin constituting the composition for inkjet may be at least partially composed of particles containing a colorant, and the composition for inkjet may further contain, for example, particles made of a sulfo group-containing polyester resin that do not contain a colorant.

[0085] However, the proportion of the sulfo group-containing polyester resin that does not constitute the particles relative to the total amount of sulfo group-containing polyester resin contained in the composition for inkjet is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

[0086] <1-4> Water-soluble organic solvents The inkjet composition may contain a water-soluble organic solvent.

[0087] This makes it possible to, for example, suitably adjust the viscosity of the composition for inkjet and increase the moisture retention of the composition for inkjet, thereby enabling more stable droplet ejection by the inkjet method.

[0088] Examples of the water-soluble organic solvent contained in the composition for inkjet include glycerin, propylene glycol, and 2-pyrrolidone.

[0089] By including these solvents, the evaporation rate can be slowed down due to the excellent moisturizing ability, and more stable droplet ejection can be achieved.

[0090] The lower limit of the content of the water-soluble organic solvent in the composition for inkjet is not particularly limited, but is preferably 0% by mass, more preferably 1.0% by mass, and even more preferably 3.0% by mass. The upper limit of the content of the water-soluble organic solvent in the composition for inkjet is not particularly limited, but is preferably 30.0% by mass, more preferably 25.0% by mass, and even more preferably 20.0% by mass. This allows the effects of including the water-soluble organic solvent to be more pronounced.

[0091] <1-5> Other ingredients The inkjet composition may contain components other than the components described above. Hereinafter, in this section, such components will also be referred to as "other components."

[0092] Other components include, for example, resin materials other than sulfo group-containing polyester resins, various surfactants, various dispersants, emulsifiers, penetrating agents such as triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, diethylene glycol monomethyl ether, 1,2-hexanediol, 1,2-pentanediol, 1,2-butanediol, and 3-methyl-1,5-pentanediol, drying inhibitors such as triethanolamine, pH adjusters, chelating agents such as ethylenediaminetetraacetate, preservatives, antifungal agents, and rust inhibitors. Suitable preservatives and antifungal agents include, for example, compounds having an isothiazolinone ring structure in the molecule.

[0093] Furthermore, when the composition for inkjet contains, in addition to the sulfo group-containing polyester resin, a polyester resin that does not have a sulfo group as a resin material other than the sulfo group-containing polyester resin, it is possible to preferably achieve a distribution of sulfo groups in the particles, even if, for example, the sulfo group-containing polyester resin contains sulfo groups uniformly within the molecule.

[0094] Furthermore, if the inkjet composition contains a surfactant, the inkjet composition can have more suitable wettability with respect to the recording medium, which is advantageous in obtaining better image quality.

[0095] As the surfactant contained in the composition for inkjet, various surfactants such as anionic surfactants, cationic surfactants, and nonionic surfactants can be used.

[0096] More specifically, examples of surfactants contained in the inkjet composition include acetylene-based surfactants, silicone-based surfactants, and fluorine-based surfactants.

[0097] The content of other components in the composition for inkjet is preferably 6.0% by mass or less, more preferably 5.0% by mass or less. When the composition for inkjet contains multiple types of components as other components, it is preferable that the total content of these components satisfies the above condition.

[0098] <1-6> Other conditions The viscosity of the inkjet composition at 25°C is not particularly limited, but is preferably 9.0 mPa·s or less, more preferably 8.0 mPa·s or less, and even more preferably 7.0 mPa·s or less. The lower limit of the viscosity of the inkjet composition at 25°C is not particularly limited, but is preferably 2.0 mPa·s, more preferably 3.0 mPa·s, and even more preferably 4.0 mPa·s. This further improves the ejection stability of the inkjet composition.

[0099] The viscosity was measured at 25°C using a viscoelasticity tester such as the MCR-300 manufactured by Pysica, with a shear rate of 10 [s -1 ] to 1000[s -1 ] and measure the viscosity at a Shear Rate of 200.

[0100] The lower limit of the surface tension of the inkjet composition at 25° C. is not particularly limited, but is preferably 20 mN / m, more preferably 21 mN / m, and even more preferably 23 mN / m. The upper limit of the surface tension of the inkjet composition at 25° C. is not particularly limited, but is preferably 50 mN / m, more preferably 40 mN / m, and even more preferably 30 mN / m.

[0101] This makes it more difficult for nozzle clogging and the like to occur in the inkjet recording device, and improves the ejection stability of the inkjet composition. Furthermore, even if nozzle clogging does occur, the inkjet composition can be more easily recovered by capping the nozzle, i.e., by capping.

[0102] The surface tension can be measured by the Wilhelmy method using a surface tensiometer such as the CBVP-7 manufactured by Kyowa Interface Science Co., Ltd.

[0103] When the inkjet composition of the present invention is an ink, the ink is usually applied to a recording device using an inkjet method in a state where it is contained in a container such as a cartridge, a bag, a tank, etc. In other words, the recording device of the present invention is equipped with a container such as an ink cartridge that contains the ink as the inkjet composition of the present invention.

[0104] <2> Method for producing inkjet composition Next, a method for producing the composition for inkjet recording will be described.

[0105] <2-1> First method The composition for inkjet of the present invention can be produced, for example, by the first method described below.

[0106] That is, the first method includes an emulsified suspension preparation step of preparing an emulsified suspension by mixing a first composition containing a sulfo group-containing polyester resin, a colorant, and an organic solvent with a second composition containing water, and an organic solvent removal step of removing at least a portion of the organic solvent from the emulsified suspension.

[0107] In the first method, first, a first composition containing a sulfo group-containing polyester resin, a colorant, and an organic solvent is prepared.

[0108] The first composition may be prepared by mixing the components simultaneously, or may be prepared by mixing the components in two or more separate stages.

[0109] For example, after preparing a kneaded mixture of the sulfo group-containing polyester resin and the coloring material, the kneaded mixture may be mixed with an organic solvent to dissolve or disperse the sulfo group-containing polyester resin and the coloring material.

[0110] As the organic solvent, for example, one having a solubility in water at 25° C. of 0.1 g / 100 g H2O or more and 30 g / 100 g H2O or less can be suitably used.

[0111] Examples of such organic solvents include ethers such as tetrahydrofuran, ketones such as methyl ethyl ketone and methyl isopropyl ketone, and esters such as ethyl acetate and isopropyl acetate. One or more selected from these can be used in combination.

[0112] The organic solvent is preferably one that dissolves or disperses the sulfo group-containing polyester resin and is easy to remove in a subsequent step, and therefore, an organic solvent with a relatively low boiling point is preferred.

[0113] From this viewpoint, the organic solvent is preferably tetrahydrofuran, methyl ethyl ketone, or ethyl acetate, and more preferably tetrahydrofuran or methyl ethyl ketone.

[0114] In addition, components other than the sulfo group-containing polyester resin, colorant, and organic solvent may be used in preparing the first composition. Such components include, for example, basic compounds, emulsifiers, and the like.

[0115] <2-1-1> Emulsion suspension preparation process In the emulsion suspension preparation step, the first composition and the second composition containing water are mixed to prepare an emulsion suspension.

[0116] The emulsified suspension thus obtained is in a state in which a dispersoid containing a sulfo group-containing polyester resin, a coloring material, and an organic solvent is dispersed in an aqueous dispersion medium.

[0117] The second composition may contain at least water, for example, pure water, or a liquid containing components other than water, such as a basic component.

[0118] The basic component may be mixed with the first composition prior to mixing the first composition with the second composition.

[0119] Examples of basic compounds include inorganic bases such as sodium hydroxide, potassium hydroxide, and ammonia, and organic bases such as diethylamine, triethylamine, and isopropylamine, and one or more selected from these can be used in combination.

[0120] The first composition and the second composition may be mixed, for example, by supplying the second composition to the first composition, or by supplying the first composition to the second composition, but is preferably mixed by adding the second composition dropwise to the first composition. This makes it possible to more suitably carry out phase inversion emulsification of the first composition, and more suitably form the particles having the average particle size described above.

[0121] Furthermore, the first composition and the second composition are preferably mixed by supplying the second composition to the first composition while stirring the first composition. This makes it possible to more suitably carry out phase inversion emulsification of the first composition, and more suitably form the particles having the average particle size described above.

[0122] The lower limit of the ratio of the organic solvent to the total amount of the organic solvent and water in the emulsified suspension at the end of the emulsified suspension preparation process is preferably 15% by mass, more preferably 20%, and the upper limit of the ratio of the organic solvent to the total amount of the organic solvent and water in the emulsified suspension at the end of the emulsified suspension preparation process is preferably 35% by mass, more preferably 30%.

[0123] <2-1-2> Organic solvent removal process In the organic solvent removal step, at least a portion of the organic solvent is removed from the emulsified suspension.

[0124] As a result, solid particles containing a colorant and a sulfo group-containing polyester resin are formed, which correspond to the particles constituting the inkjet composition of the present invention.

[0125] The organic solvent removal step can be carried out, for example, by heating the emulsified suspension or placing the emulsified suspension in a reduced pressure environment.

[0126] The dispersion obtained in the organic solvent removal step, in which solid particles containing a colorant and a sulfo group-containing polyester resin are dispersed in an aqueous dispersion medium, may be used as the inkjet composition of the present invention as is, or the dispersion may be mixed with other components to form the inkjet composition of the present invention.

[0127] After the organic solvent removal step, post-treatment steps such as washing and drying may be carried out. This makes it possible to remove unnecessary components, and to obtain a composition for inkjet with a more reliably adjusted composition.

[0128] The particles contained in the dispersion obtained in the organic solvent removal step can be washed by, for example, separating the particles from the dispersion constituting the dispersion using a separation means such as a centrifuge, a filter press, or a belt filter to obtain a microparticle cake, followed by stirring and dispersing the microparticle cake in water and further dehydrating it.

[0129] After dehydration, a drying treatment may be carried out as necessary. For the drying treatment, for example, a mixing vacuum dryer such as a Ribocone dryer (manufactured by Okawahara Manufacturing Co., Ltd.) or a Nauta Mixer (manufactured by Hosokawa Micron Corporation), or a fluidized bed dryer such as a fluidized bed dryer (manufactured by Okawahara Manufacturing Co., Ltd.) or a vibration fluidized bed dryer (manufactured by Chuo Kakoki Co., Ltd.) can be used.

[0130] When the dehydration treatment and drying treatment are carried out, the washed particles can be mixed with other components containing at least water to obtain the inkjet composition of the present invention.

[0131] In the organic solvent removal step, it is sufficient to remove at least a portion of the organic solvent contained in the emulsified suspension, particularly the organic solvent contained in the dispersoid of the emulsified suspension, and complete removal is not necessary. Even in such a case, the remaining organic solvent can usually be sufficiently removed by post-treatment steps such as washing and drying. Furthermore, a small amount of organic solvent may remain in the final inkjet composition.

[0132] <2-2> Second method The composition for inkjet of the present invention can be produced, for example, by the second method described below.

[0133] That is, the second method comprises an emulsified dispersion preparation step of mixing a first composition containing a sulfo group-containing polyester resin and an organic solvent with a second composition containing water to prepare an emulsified dispersion; an organic solvent removal step of removing at least a portion of the organic solvent from the emulsified dispersion to obtain an aqueous dispersion of the sulfo group-containing polyester resin; and a colorant mixing step of mixing the aqueous dispersion of the sulfo group-containing polyester resin with a colorant while heating, thereby incorporating the colorant into particles composed of a material containing the sulfo group-containing polyester resin.

[0134] In the second method, first, a first composition containing a sulfo group-containing polyester resin and an organic solvent is prepared.

[0135] The organic solvent preferably has a boiling point of 90°C or less under 1 atmospheric pressure, more preferably 80°C or less.

[0136] This allows the organic solvent to be suitably removed in the subsequent organic solvent removal step, and makes it possible to suitably prevent excess organic solvent from remaining in the final inkjet composition.

[0137] Examples of organic solvents include ethers such as tetrahydrofuran; ketones such as methyl ethyl ketone and methyl isopropyl ketone; and esters such as ethyl acetate and isopropyl acetate. One or more selected from these can be used in combination.

[0138] In addition, components other than the sulfo group-containing polyester resin and the organic solvent may be used to prepare the first composition. Such components include, for example, basic compounds, emulsifiers, and the like.

[0139] <2-2-1> Emulsion dispersion preparation process In the emulsion dispersion preparation step, the first composition and the second composition containing water are mixed to prepare an emulsion dispersion.

[0140] The emulsified dispersion thus obtained is in a state in which a dispersoid containing a sulfo group-containing polyester resin and an organic solvent is dispersed in an aqueous dispersion medium.

[0141] The second composition may contain at least water, for example, pure water, or a liquid containing components other than water, such as a basic component.

[0142] The basic component may be mixed with the first composition prior to mixing the first composition with the second composition.

[0143] Examples of basic compounds include inorganic bases such as sodium hydroxide, potassium hydroxide, and ammonia, and organic bases such as diethylamine, triethylamine, isopropylamine, triethanolamine, and tripropanolamine, and one or more selected from these can be used in combination.

[0144] The first composition and the second composition may be mixed, for example, by supplying the second composition to the first composition, or by supplying the first composition to the second composition, but is preferably mixed by adding the second composition dropwise to the first composition. This makes it possible to more suitably carry out phase inversion emulsification of the first composition, and more suitably form the particles having the average particle size described above.

[0145] Furthermore, the first composition and the second composition are preferably mixed by supplying the second composition to the first composition while stirring the first composition.

[0146] This makes it possible to more suitably carry out phase inversion emulsification of the first composition, and more suitably form the particles having the average particle size described above.

[0147] This step may be carried out, for example, while heating to a temperature equal to or lower than the boiling point of the organic solvent. This makes it possible to achieve a state in which sulfo groups are favorably distributed near the surface of a dispersoid containing a sulfo group-containing polyester resin and an organic solvent, and in a subsequent step, it is possible to favorably form the particles having sulfo groups favorably distributed near the surface.

[0148] The lower limit of the ratio of the organic solvent to the total amount of the organic solvent and water in the emulsion dispersion at the end of the emulsion dispersion preparation process is preferably 20% by mass, more preferably 23%, and the upper limit of the ratio of the organic solvent to the total amount of the organic solvent and water in the emulsion dispersion at the end of the emulsion dispersion preparation process is preferably 35% by mass, more preferably 30%.

[0149] <2-2-2> Organic solvent removal process In the organic solvent removal step, at least a portion of the organic solvent is removed from the emulsified dispersion.

[0150] As a result, solid particles containing the sulfo group-containing polyester resin are formed, and an aqueous dispersion of the sulfo group-containing polyester resin is obtained.

[0151] The organic solvent removal step can be carried out, for example, by heating the emulsified dispersion or placing the emulsified dispersion in a reduced pressure environment, but is preferably carried out by at least heating the emulsified dispersion.

[0152] This makes it possible to make the sulfo groups be preferentially distributed near the surface of the solid particles containing the sulfo group-containing polyester resin, and more preferably form particles having sulfo groups preferentially distributed near the surface contained in the final composition for inkjet.

[0153] When the emulsified dispersion is heated in this step, the heating temperature is preferably higher than the boiling point of the organic solvent and lower than the boiling point of water.

[0154] In the organic solvent removal step, it is sufficient to remove at least a portion of the organic solvent contained in the emulsion dispersion, particularly the organic solvent contained in the dispersoid of the emulsion dispersion, and complete removal is not necessary. Even in such a case, the remaining organic solvent can be sufficiently removed in a subsequent step. Furthermore, a small amount of organic solvent may remain in the finally obtained composition for inkjet.

[0155] <2-2-3> Color material mixing process In the colorant mixing step, the water dispersion of the sulfo group-containing polyester resin and the colorant are mixed together to incorporate the colorant into particles made of a material containing the sulfo group-containing polyester resin.

[0156] In order to efficiently incorporate the coloring material into the particles made of a material containing a sulfo group-containing polyester resin, this step is carried out under heating.

[0157] The lower limit of the heating temperature in this step is preferably 40°C, more preferably 45°C, and even more preferably 50°C. The upper limit of the heating temperature in this step is preferably 100°C, more preferably 98°C, and even more preferably 95°C.

[0158] The lower limit of the heating time in this step is preferably 5 minutes, more preferably 10 minutes, and even more preferably 20 minutes, and the upper limit of the heating time in this step is preferably 300 minutes, more preferably 240 minutes, and even more preferably 180 minutes.

[0159] The heating in this step is preferably carried out while stirring the mixture of the aqueous dispersion of the sulfo group-containing polyester resin and the coloring material.

[0160] In this step, components other than the colorant may be mixed with the aqueous dispersion of the sulfo group-containing polyester resin together with the colorant.

[0161] The mixing of the sulfo group-containing polyester resin with the aqueous dispersion may be carried out in two or more stages.

[0162] After the colorant mixing step, post-treatment steps such as washing and drying may be carried out. This makes it possible to remove unnecessary components, and to obtain a composition for inkjet with a more reliably adjusted composition.

[0163] The particles contained in the dispersion obtained in the colorant mixing step can be washed by, for example, separating the particles from the dispersion constituting the dispersion using a separation means such as a centrifuge, a filter press, or a belt filter to obtain a microparticle cake, and then stirring and dispersing the microparticle cake in water, and further dehydrating the cake.

[0164] After dehydration, a drying treatment may be carried out as necessary. For the drying treatment, for example, a mixing vacuum dryer such as a Ribocone dryer (manufactured by Okawahara Manufacturing Co., Ltd.) or a Nauta Mixer (manufactured by Hosokawa Micron Corporation), or a fluidized bed dryer such as a fluidized bed dryer (manufactured by Okawahara Manufacturing Co., Ltd.) or a vibration fluidized bed dryer (manufactured by Chuo Kakoki Co., Ltd.) can be used.

[0165] When the dehydration treatment and drying treatment are carried out, the washed particles can be mixed with other components containing at least water to obtain the inkjet composition of the present invention.

[0166] <3> Inkjet recording method Next, the ink jet recording method of the present invention will be described.

[0167] The inkjet recording method of the present invention includes a discharge step of discharging the inkjet composition of the present invention by an inkjet method.

[0168] This makes it possible to provide an inkjet recording method that can stably eject droplets by the inkjet method and is suitable for producing recorded matter having a recorded portion with excellent color development. In particular, it is possible to exhibit excellent color development on various recording media. Furthermore, it is possible to provide excellent fixability and adhesion strength for a recorded portion formed using the inkjet composition.

[0169] The inkjet recording method of the present invention preferably further comprises, after the ejection step, a heating step of heating the recording medium to which the inkjet composition has been attached. This further improves the color development of the recorded portion and the fixation of the recorded portion to the recording medium.

[0170] <3-1>Discharge process In the ejection step, the inkjet composition is ejected by an inkjet method and applied to a recording medium. The ejection of the inkjet composition by the inkjet method can be performed using a known inkjet recording device. As the ejection method, a piezo method, a method in which ink is ejected by bubbles generated by heating the ink, or the like can be used. Among these, the piezo method is preferred from the viewpoint of preventing deterioration of the inkjet composition, etc.

[0171] In the ejection step, a plurality of types of inkjet compositions according to the present invention may be used in combination. More specifically, for example, a plurality of types of inkjet compositions having different compositions or contents of coloring materials may be used in combination.

[0172] In the ejection step, an ink other than the ink-jet composition according to the present invention may be used in combination.

[0173] <3-2> Recording media The constituent materials of the recording medium are not particularly limited, but examples include resin materials such as polyurethane, polyethylene, polypropylene, polyester, polyamide, and acrylic resin; paper such as cardboard, plain paper, and inkjet paper; glass, metal, ceramics, leather, wood, pottery, and concrete; fibers composed of at least one of these; various natural fibers such as silk, wool, cotton, linen, polyester, polyamide (nylon), acrylic, polyurethane, cellulose, linter, rayon, cupra, and acetate; synthetic fibers; and semi-synthetic fibers. One or more selected from these may be used in combination. Furthermore, the recording medium may have a three-dimensional shape, such as a sheet, sphere, or rectangular parallelepiped.

[0174] When the recording medium is made of a material containing polyester, the adhesion between the recording medium and the recording area formed by the inkjet composition of the present invention can be made even better.

[0175] In particular, it is preferable that the recording medium is a fabric. Dyeing of fabrics is in high demand for printed T-shirts and the like, and printing by ironing and the like is widespread. However, printed matter in which a printed portion is provided on such fabrics is required to have a texture, particularly smoothness, suppleness, and softness, as well as durability of the printed portion. The present invention can meet these requirements. Therefore, when the recording medium is fabric, the effects of the present invention are more pronounced.

[0176] As the fabric, various woven fabrics such as plain weave, twill weave, satin weave, varied plain weave, varied twill weave, varied satin weave, patterned weave, single-layer weave, double weave, multiple weave, warp pile weave, weft pile weave, and leno weave can be used.

[0177] The thickness of the fibers constituting the fabric can be, for example, 10 d or more and 100 d or less.

[0178] Examples of fibers that can be used to make fabrics include polyester fibers, nylon fibers, triacetate fibers, diacetate fibers, polyamide fibers, cellulose fibers, and blends of two or more of these fibers. Blends of these fibers with regenerated fibers such as rayon or natural fibers such as cotton, silk, and wool may also be used.

[0179] Furthermore, a film that is used by bending and stretching can also be suitably used as the recording medium, which more significantly exhibits the effects of the present invention, such as the ability to form a recording part that has low tackiness, an excellent texture, and excellent elasticity and adhesion to the recording medium.

[0180] <3-3>Heating process In this embodiment, after the above-described ejection step, the recording medium to which the inkjet composition has been applied is heated.

[0181] The lower limit of the heating temperature of the recording medium in this step is not particularly limited, but is preferably 100° C., more preferably 105° C., and even more preferably 110° C. The upper limit of the heating temperature of the recording medium in this step is not particularly limited, but is preferably 160° C., more preferably 155° C., and even more preferably 150° C.

[0182] This allows the effects of providing the heating step as described above to be more pronounced. Furthermore, the energy required for producing recorded materials can be reduced, further improving the productivity of recorded materials. Furthermore, recording media with relatively low heat resistance can also be suitably applied, further expanding the range of recording media options. Furthermore, it is possible to suitably prevent undesired discoloration, changes in optical density, and the like caused by heating after the production of recorded materials, such as washing / cleaning with hot water, heated drying in a dryer, ironing, and other heat treatments. Furthermore, when the heating temperature in this step is within the above-mentioned range, deterioration in the texture of the recorded portion can be more effectively prevented.

[0183] Although it depends on the heating temperature of the recording medium in this process, the lower limit of the heating time of the recording medium in this process is preferably 0.2 seconds, more preferably 1 second, and even more preferably 5 seconds, and the upper limit of the heating time of the recording medium in this process is preferably 300 seconds, more preferably 60 seconds, and even more preferably 30 seconds.

[0184] This allows the effects of providing the heating step as described above to be more pronounced. Furthermore, the energy required for producing recorded materials can be reduced, further improving the productivity of recorded materials. Furthermore, recording media with relatively low heat resistance can also be suitably applied, further expanding the range of recording media options. Furthermore, it is possible to suitably prevent undesired discoloration, changes in optical density, and the like caused by heating after the production of recorded materials, such as washing / cleaning with hot water, heated drying in a dryer, ironing, and other heat treatments. Furthermore, when the heating temperature in this step is within the above-mentioned range, deterioration in the texture of the recorded portion can be more effectively prevented.

[0185] In addition, this step may be carried out by heating the surface of the recording medium to which the inkjet composition is adhered while the surface is spaced apart from a heating member, or by heating the recording medium to which the inkjet composition is adhered while the recording medium and the heating member are in close contact with each other.

[0186] The heating step may be carried out simultaneously with the ejection step. More specifically, for example, the recording medium to which the inkjet composition is applied may be heated in advance, and a heat treatment may be carried out after the inkjet composition has come into contact with the recording medium. In this case, for example, heating may be carried out continuously before and after the inkjet composition is applied to the recording medium, or heating of the recording medium to which the inkjet composition is applied may be interrupted and then resumed.

[0187] <4> Recording device Next, the recording device will be described. FIG. 1 is a schematic perspective view of a recording apparatus according to a preferred embodiment.

[0188] In the following description, an on-carriage type printer in which ink cartridges are mounted on a carriage is used as an example of the recording device. In this embodiment, the recording device is not limited to an on-carriage type printer, and may be, for example, an off-carriage type printer in which the ink cartridges are fixed externally.

[0189] The printer, which is a recording device, described below is a serial printer in which an inkjet head for recording is mounted on a carriage that moves in a predetermined direction, and the inkjet head moves in conjunction with the movement of the carriage, thereby ejecting droplets onto the recording medium. The recording device of the present invention is not limited to a serial printer, and may also be, for example, a line printer. A line printer is a printer in which the inkjet head is formed wider than the width of the recording medium, and ejects droplets onto the recording medium without moving the inkjet head.

[0190] In the drawings used in the following description, the scale of each component has been changed appropriately so that each component can be recognized.

[0191] The recording apparatus 1 is equipped with an inkjet head 2 that ejects the inkjet composition of the present invention described above toward a recording medium M by an inkjet method, and is used to carry out the inkjet recording method of the present invention described above.

[0192] This makes it possible to provide a recording device that has a recording section with excellent texture and is capable of suitably producing a recording material with excellent durability.

[0193] In particular, the recording device 1 shown in FIG. 1 includes an inkjet head 2, an ink cartridge 3, a carriage 4, a platen 5, a heating mechanism 6, a carriage moving mechanism 7, a medium feeding mechanism 8, a guide rod 9, a linear encoder 10, and a control unit CONT.

[0194] The control unit CONT controls the overall operation of the recording apparatus 1. The carriage 4 carries an inkjet head 2 (described later) and also detachably mounts an ink cartridge 3 for supplying an inkjet composition to the inkjet head 2 .

[0195] The platen 5 is disposed below the inkjet head 2, and the recording medium M is transported through the platen 5.

[0196] The heating mechanism 6 heats the recording medium M. In this way, by having the heating mechanism 6 that heats the recording medium M, it is possible to suitably fix the recorded portion made of the inkjet composition to the recording medium M. In particular, it is possible to suitably fix the recorded portion without using a device separate from the recording device 1.

[0197] The carriage movement mechanism 7 moves the carriage 4 in the width direction of the recording medium M. The medium feeding mechanism 8 transports the recording medium M in a medium feeding direction. Here, the medium width direction is the main scanning direction, which is the scanning direction of the inkjet head 2. The medium feeding direction is a direction perpendicular to the main scanning direction, and is the sub-scanning direction in which the recording medium M moves.

[0198] The inkjet head 2 is a means for depositing the inkjet composition onto the recording medium M, and is provided with a plurality of nozzles (not shown) for ejecting the inkjet composition on the surface facing the recording medium M to which the ink is to be deposited. These nozzles are arranged in a row, and a nozzle surface is formed on the surface of the nozzle plate.

[0199] As a method for ejecting the inkjet composition from a nozzle, for example, a piezo method can be mentioned in which pressure and a recording information signal are simultaneously applied to the inkjet composition by a piezoelectric element, thereby ejecting and recording droplets of the inkjet composition.

[0200] In Figure 1, the ink cartridges 3 that supply the inkjet composition to the inkjet head 2 consist of four independent cartridges. Each of the four cartridges is filled with, for example, a different type of inkjet composition. The ink cartridges 3 are detachably attached to the inkjet head 2. In the example of Figure 1, the number of cartridges is four, but this is not limiting and any desired number of cartridges can be installed.

[0201] The carriage 4 is attached while being supported by a guide rod 9, which is a support member installed in the main scanning direction, and moves in the main scanning direction along the guide rod 9 by a carriage movement mechanism 7. In the example of Fig. 1, the carriage 4 moves in the main scanning direction, but this is not limiting, and the carriage 4 may move in the sub-scanning direction in addition to the movement in the main scanning direction.

[0202] The installation position of the heating mechanism 6 is not particularly limited as long as it is located in a position where it can heat the recording medium M. In the example of Fig. 1, the heating mechanism 6 is installed on the platen 5 at a position facing the inkjet head 2. When the heating mechanism 6 is installed at a position facing the inkjet head 2, it is possible to reliably heat the position on the recording medium M where the inkjet composition is to be adhered, and it is possible to efficiently dry the inkjet composition adhered to the recording medium M.

[0203] Examples of the heating mechanism 6 include a print heater mechanism that heats the recording medium M by contacting it with a heat source, a mechanism that irradiates infrared rays or microwaves, which are electromagnetic waves with a maximum wavelength of around 2,450 MHz, and a dryer mechanism that blows hot air.

[0204] The control of the various conditions for heating the recording medium M by the heating mechanism 6, such as the timing of heating, the heating temperature, the heating time, etc., is performed by the control unit CONT.

[0205] The recording apparatus 1 may have a second heating mechanism (not shown) in addition to the heating mechanism 6. In that case, the second heating mechanism is installed downstream of the heating mechanism 6 in the transport direction of the recording medium M. This improves the drying property of the inkjet composition adhered to the recording medium M. Any of the mechanisms described for the heating mechanism 6 can be used as the second heating mechanism.

[0206] The linear encoder 10 detects the position of the carriage 4 in the main scanning direction using a signal. The signal detected by the linear encoder 10 is sent to the control unit CONT as position information. The control unit CONT recognizes the scanning position of the inkjet head 2 based on the position information from the linear encoder 10 and controls the recording operation, i.e., the ejection operation, of the inkjet head 2. The control unit CONT is configured to be able to variably control the movement speed of the carriage 4.

[0207] <5> Recorded material Next, the recorded matter according to the present invention will be described.

[0208] The recorded matter according to the present invention has a recorded portion formed using the inkjet composition according to the present invention.

[0209] This makes it possible to provide a recorded matter having a recorded portion with excellent color development, and also makes it possible to improve the fixability and adhesive strength of the recorded portion to the recording medium. As the recording medium, the above-mentioned ones can be suitably used.

[0210] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these.

[0211] For example, the inkjet composition of the present invention may be any composition that can be used for ejection by an inkjet method, and does not necessarily have to be applied to the methods described above.

[0212] Furthermore, for example, the present invention may be applied to a method having other steps in addition to the steps described above.

[0213] In this case, the pre-treatment step may include, for example, a step of applying a coating layer to the recording medium.

[0214] An example of an intermediate processing step is a step of preheating the recording medium. Furthermore, examples of post-processing steps include a step of cleaning the recording medium.

[0215] The inkjet composition of the present invention may be produced by any method, and is not limited to the method described above. For example, the inkjet composition of the present invention may contain particles formed by emulsion polymerization as particles containing a colorant and a sulfo group-containing polyester resin. [Example]

[0216] Next, specific examples of the present invention will be described. <6> Polyester resin synthesis (Synthesis Example A1) Dimethyl terephthalate, dimethyl isophthalate, 5-sodium dimethyl sulfoisophthalate, ethylene glycol, neopentyl glycol, and tetrabutoxy titanate were charged in a predetermined ratio into an autoclave equipped with a thermometer and a stirrer, and the mixture was heated at 180-230°C for 120 minutes to carry out an ester exchange reaction. The reaction system was then heated to 250°C, and the pressure of the system was reduced to 1-10 mmHg, allowing the reaction to continue for 60 minutes, yielding a sulfo group-containing polyester resin.

[0217] NMR analysis of the resulting sulfo-containing polyester resin revealed that it contained, as diol components, 55 mol% ethylene glycol and 45 mol% neopentyl glycol, and as dicarboxylic acid components, 50 mol% terephthalic acid, 45 mol% isophthalic acid, and 5 mol% 5-sodium sulfoisophthalic acid. The sulfo-containing polyester resin had a number average molecular weight of 3,500 and a glass transition temperature of 58°C. The sulfo-containing polyester resin obtained in this synthesis example had a sulfur atom content of 0.25 at% as determined by energy dispersive X-ray analysis.

[0218] (Synthesis examples A2, A3) Sulfo group-containing polyester resins were synthesized in the same manner as in Synthesis Example A1, except that the amounts of each raw material were changed. The sulfo group-containing polyester resin obtained in Synthesis Example A2 had a sulfur atomic content of 0.40 at% as determined by energy dispersive X-ray analysis, and the sulfo group-containing polyester resin obtained in Synthesis Example A3 had a sulfur atomic content of 0.80 at% as determined by energy dispersive X-ray analysis.

[0219] (Synthesis example A4) A polyester resin was synthesized in the same manner as in Synthesis Example A1, except that 5-sodium dimethyl sulfoisophthalate was not used and the amounts of the other raw materials were changed. The polyester resin obtained in this Synthesis Example did not have a sulfo group in the molecule and did not contain a sulfur atom.

[0220] <7> Preparation of inkjet composition Example 1 In a 1-liter three-neck flask equipped with a stirrer and a reflux condenser, 80.0 parts by mass of the sulfo group-containing polyester resin synthesized in Synthesis Example A1 and 20.0 parts by mass of the sulfo group-containing polyester resin synthesized in Synthesis Example A2 were dissolved in 200.0 parts by mass of tetrahydrofuran at 60°C, and then 400.0 parts by mass of ion-exchanged water was added and the mixture was stirred at 600 rpm for 10 minutes to obtain an emulsified dispersion.

[0221] Next, the emulsified dispersion was heated and stirred up to 100° C. to evaporate the tetrahydrofuran, thereby obtaining a 40% by mass aqueous dispersion of the sulfo group-containing polyester resin.

[0222] Next, to 100.0 parts by mass of the 40% by mass aqueous dispersion of sulfo group-containing polyester resin obtained as described above, 3.0 parts by mass of CI Disperse Red 60 as a sublimation dye used as a colorant, 30.1 parts by mass of distilled water, 5.0 parts by mass of propylene glycol, 5.0 parts by mass of Silface SAG503A manufactured by Nissin Chemical Co., Ltd., and 0.2 parts by mass of triethanolamine were added, and the mixture was stirred at 90°C for 2 hours to obtain an inkjet composition with a solid content of colored microparticles of 30.0% by mass.

[0223] Examples 2 to 6 A composition for inkjet printing was prepared in the same manner as in Example 1, except that the type and amount of each component was changed to obtain the composition shown in Table 1.

[0224] (Comparative Examples 1 and 2) A composition for inkjet printing was prepared in the same manner as in Example 1, except that the type and amount of each component was changed to obtain the composition shown in Table 1.

[0225] (Comparative Example 3) An inkjet composition was prepared in the same manner as in Example 1, except that the type and amount of each component was changed to obtain the composition shown in Table 1, and the amount of tetrahydrofuran was changed from 200 g to 400 g.

[0226] <8> evaluation <8-1>Discharge stability The inkjet compositions of each of the Examples and Comparative Examples were placed in cartridges for a recording device PX-M860F (manufactured by Seiko Epson Corporation) and set into the recording device. Ten sheets of A4 MCPW paper (manufactured by Toppan Forms Co., Ltd.) were printed in full solid ink, and then 30 minutes later, ten sheets of MCPW paper (manufactured by Toppan Forms Co., Ltd.) were printed in full solid ink. Immediately after printing, a standard nozzle missing pattern was printed using the printer driver, and the number of nozzle missings was counted and evaluated according to the following criteria. The fewer the number of nozzle missings, the better the ejection stability.

[0227] AA: 0 missing nozzles. A: The number of missing nozzles is between 1 and 9. B: The number of missing nozzles is between 10 and 35. C: The number of missing nozzles is 36 or more.

[0228] <8-2> Color development For each of the inkjet compositions of the Examples and Comparative Examples, an M105 recording device (manufactured by Seiko Epson Corporation) was used to print on MCPW paper (manufactured by Toppan Forms Co., Ltd.) as a recording medium in the standard plain paper mode, and the optical density (OD) value of the printed area was measured using a colorimeter (Gretag Macbeth Spectrolin: manufactured by X-rite) and evaluated according to the following criteria: The higher the optical density, the better the color development.

[0229] AA:OD value is 1.3 or higher. A: OD value is 1.1 or more but less than 1.3. B: OD value is 0.9 or more and less than 1.1. C:OD value less than 0.9.

[0230] The composition of the inkjet compositions of each of the examples and comparative examples and the evaluation results are summarized in Table 1. In the table, the sulfo-containing polyester resin synthesized in Synthesis Example A1 is indicated as "A1," the sulfo-containing polyester resin synthesized in Synthesis Example A2 is indicated as "A2," the sulfo-containing polyester resin synthesized in Synthesis Example A3 is indicated as "A3," the polyester resin synthesized in Synthesis Example A4 is indicated as "A4," CI Disperse Red 60 is indicated as "DR60," CI Solvent Blue 5 is indicated as "SB5," propylene glycol is indicated as "PG," Nissin Chemical Silface SAG503A is indicated as "SAG503A," and triethanolamine is indicated as "TEA." The average particle size column in the table shows the average particle size determined by measurement using a zeta potential / particle size measurement system "ELSZ-1000ZS" (manufactured by Otsuka Electronics Co., Ltd.). In the table, the viscosity column indicates the viscosity measured at 25°C with a viscoelasticity tester MCR-300 (manufactured by Pysica) at a shear rate of 10 [s -1 ] to 1000[s -1The viscosity was measured at a shear rate of 200 while increasing the viscosity to 100°C. The inkjet compositions of each example had a surface tension ranging from 23 mN / m to 30 mN / m. The surface tension was measured by the Wilhelmy method at 25°C using a surface tensiometer (CBVP-7, manufactured by Kyowa Interface Science Co., Ltd.). The sulfo group-containing polyester resins contained in the inkjet compositions of each example had an acid value ranging from 1.0 KOHmg / g to 15.0 KOHmg / g, a number average molecular weight ranging from 1,500 to 20,000, and a glass transition point ranging from 40°C to 80°C.

[0231] [Table 1]

[0232] As is clear from Table 1, excellent results were obtained in the present invention. In contrast, satisfactory results were not obtained in the comparative examples.

[0233] Using a PX-M860F (Seiko Epson Corporation) as the recording apparatus and a cotton fabric as the recording medium, the recording medium to which the inkjet composition had been applied was subjected to a heat treatment at 150°C for 5 seconds by contacting an iron as a heating member with the side of the recording medium to which the inkjet composition had been applied, and the resulting recorded matter was evaluated in the same manner as in <8-2> above, with the same results as above. Furthermore, recorded matters were produced in the same manner as above, except that the heating temperature in the heating step was changed within the range of 100°C to 160°C and the heating time was changed within the range of 0.2 seconds to 300 seconds, and the same results as above were obtained. [Explanation of symbols]

[0234] 1...recording device, 2...inkjet head, 3...ink cartridge, 4...carriage, 5...platen, 6...heating mechanism, 7...carriage movement mechanism, 8...medium feeding mechanism, 9...guide rod, 10...linear encoder, M...recording medium, CONT...control section

Claims

1. A composition for inkjet use that is applied to fabric, comprising: The ink contains water, a polyester resin having a sulfo group, and a colorant, the colorant is contained in particles made of a material containing the polyester resin, the coloring material includes at least one selected from the group consisting of sublimation dyes, oil-based dyes, and disperse dyes; The particles have an average particle size of 100 nm or less, and the content of the particles in the composition for inkjet is 15% by mass or more.

2. The inkjet composition according to claim 1, which has a viscosity at 25°C of 9.0 mPa·s or less.

3. 3. The composition for ink jet recording according to claim 1, wherein the amount of sulfur atoms contained in the polyester resin is 0.60 at % or less.

4. The composition for inkjet according to claim 1 , wherein the particles contain a plurality of types of polyester resins having different sulfo group contents.

5. An inkjet recording method, comprising a step of ejecting the inkjet composition according to claim 1 by an inkjet method.

6. The inkjet recording method according to claim 5 , further comprising, after the ejection step, a heating step of heating the fabric to which the inkjet composition has been attached.

7. The ink jet recording method according to claim 6, wherein the heating temperature of the fabric in the heating step is 100°C or higher and 160°C or lower.

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