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 dispersion stability of a resin material or the like in inkjet ink and is excellent in color development property, and an inkjet recording method which can stably discharge droplets by an 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, a coloring material, and a polymer dispersion agent having an anionic group, wherein the coloring material is contained in particles composed of a material containing the polyester resin, and a ratio X1[mol%] of the sulfo group to the total constituent monomer of the polyester resin is smaller than a ratio X2[mol%] of the anionic group to the total constituent monomer of the polymer dispersion agent.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a composition for ink jet recording and an ink jet 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] Furthermore, inkjet printing has come to be applied to various recording media other than paper, such as fabrics, films, and cardboard.

[0004] Although the use of water-based inks is required from the viewpoints of ease of use and safety, it is difficult to obtain a sufficiently excellent coating strength with water-based inks. Therefore, inkjet inks containing resin materials are used, but when ordinary polyesters or the like are used, the dispersion stability of the resin materials in the inkjet ink is low, resulting in a problem of reduced ejection stability by the inkjet method.

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

[0006] [Patent Document 1] JP 2020-158645 A Summary of the Invention [Problem to be solved by the invention]

[0007] Although the use of such an inkjet ink can improve the dispersion stability of the resin material in the inkjet ink, there is a problem in that color development is reduced. When the solid content is increased in order to improve color development, there is a problem in that the dispersion stability of the resin material in the inkjet ink is reduced.

[0008] In other words, there is a problem in that it is not possible to achieve both dispersion stability of the resin material or the like in the inkjet ink and color development. [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 includes water, a polyester resin having a sulfo group, a colorant, and a polymer dispersant having an anionic group, the color material is contained in particles made of a material containing the polyester resin, The proportion X1 [mol %] of the sulfo group relative to all constituent monomers of the polyester resin is smaller than the proportion X2 [mol %] of the anionic group relative to all constituent monomers of the polymer dispersant.

[0011] In a composition for inkjet according to another application example of the present invention, the coloring material includes at least one selected from the group consisting of sublimation dyes, oil-based dyes, and disperse dyes.

[0012] In the composition for inkjet according to another application example of the present invention, the number average molecular weight of the polyester resin is 4,000 or more and 20,000 or less.

[0013] In the composition for inkjet according to another application example of the present invention, X1 is 0.5 mol % or more and 2.5 mol % or less.

[0014] In the composition for inkjet according to another application example of the present invention, the anionic group is a sulfo group or a carboxyl group.

[0015] In the composition for inkjet according to another application example of the present invention, the number average molecular weight of the polymer dispersant is smaller than the number average molecular weight of the polyester resin.

[0016] In a composition for inkjet according to another application example of the present invention, the content of the polymer dispersant relative to 100 parts by mass of the polyester resin is 5 parts by mass or more and 25 parts by mass or less.

[0017] In a composition for inkjet according to another application example of the present invention, the polymer dispersant is a polyester-based polymer dispersant having a sulfo group as the anionic group, The X2 is 4.0 mol % or more and 7.5 mol % or less.

[0018] The 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.

[0019] Moreover, an ink jet recording method according to another application example of the present invention further includes a heating step of heating the recording medium to which the ink jet composition is attached, after the ejection step.

[0020] In the ink jet recording method according to another application example of the present invention, the heating temperature of the recording medium in the heating step is 100° C. or more and 160° C. or less. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic perspective view of a recording apparatus according to a preferred embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Preferred embodiments of the present invention will now be described in detail. <1> Inkjet composition First, the composition for inkjet of the present invention will be described.

[0023] The composition for inkjet of the present invention contains water, a polyester resin having a sulfo group, a colorant, and a polymer dispersant having an anionic group. The colorant is contained in particles made of a material containing the polyester resin, and a ratio X1 [mol %] of the sulfo group to all constituent monomers of the polyester resin is smaller than a ratio X2 [mol %] of the anionic group to all constituent monomers of the polymer dispersant.

[0024] By satisfying such conditions, the dispersion stability of the solid content in the composition for inkjet and the storage stability of the composition for inkjet can be excellent, and the color development of the recorded portion by the composition for inkjet can be excellent. In particular, excellent color development can be exhibited on various recording media. Furthermore, the composition for inkjet can be excellent in ejection stability by the inkjet method. Furthermore, the recorded portion formed by using the composition for inkjet can be excellent in fixability and adhesion strength. Furthermore, the composition for inkjet of the present invention can be applied to a method for producing a recorded matter that does not have a transfer step as described in detail later, and is preferable from the viewpoints of improving the productivity of the recorded matter, reducing the production cost of the recorded matter, saving resources, and the like.

[0025] Such excellent effects are believed to be due to the following reasons. That is, the polyester resin constituting the particles has a sulfo group, so that the hydrophilicity of the particles can be excellent. Furthermore, by using a polyester resin having a sulfo group in combination with a polymer dispersant having an anionic group, the above-mentioned effects can be obtained while suppressing the ratio of sulfo groups in the polyester resin. By suppressing the ratio of sulfo groups in the polyester resin, the affinity between a coloring material, which is generally low in hydrophilicity, and the polyester resin can be improved, and the particles composed of a material containing a polyester resin can be suitably colored with a coloring material. In other words, the coloring material can be suitably contained in the particles composed of a material containing a polyester resin dispersed in the inkjet composition. As a result, the dispersion stability of the particles in the inkjet composition, the storage stability of the inkjet composition, and the ejection stability of the inkjet composition by the inkjet method can be excellent, and the color development of the recording part formed by the inkjet composition can be excellent.

[0026] Furthermore, the coloring material is applied to the recording medium in a state where the resin material has been suitably colored, and the fixation of the recorded portion in the produced recorded matter can be excellent, and the coloring material can be suitably prevented from unintentionally falling off the recorded matter, and the coloring material can be stably held in the recorded matter. Therefore, even when the recorded matter is subjected to heat treatments such as washing / cleaning with hot water, heating and drying with a dryer, and ironing, the coloring material can be effectively prevented from unintentionally dissipating 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 more pronounced.

[0027] On the other hand, if the above conditions are not met, satisfactory results will not be obtained. For example, even if a polymer dispersant having an anionic group is used, unless a polyester resin having a sulfo group is contained, the hydrophilicity of the particles contained in the composition for inkjet cannot be sufficiently increased, and the dispersion stability of the solid content in the composition for inkjet, the storage stability of the composition for inkjet, and the ejection stability by the inkjet method are reduced.

[0028] In addition, even if a polyester resin having a sulfo group is included, if a polymer dispersant having an anionic group is not included, the above-mentioned effect cannot be sufficiently obtained unless the proportion of sulfo groups contained in the polyester resin is increased. In addition, when the proportion of sulfo groups contained in the polyester resin is increased, the affinity between the coloring material, which generally has low hydrophilicity, and the polyester resin cannot be sufficiently excellent, and it becomes difficult to include a sufficient proportion in the particles composed of a material containing the polyester resin, and the color development of the recording part formed using the composition for inkjet cannot be sufficiently excellent.

[0029] In this specification, the inkjet composition is a concept including 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 it is, or may be ejected by the inkjet method after being diluted or the like. Examples of the inkjet method 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 composition for inkjet of the present invention contains water. The water mainly has a function of imparting fluidity to the composition for inkjet, 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 composition for inkjet is not particularly limited, but is preferably 30.0% by mass, more preferably 35.0% by mass, and even more preferably 40.0% by mass. The upper limit of the water content in the composition for inkjet is not particularly limited, but is preferably 90.0% by mass, more preferably 85.0% by mass, and even more preferably 80.0% by mass.

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

[0033] <1-2> Coloring materials The composition for inkjet of the present invention contains a coloring material. The coloring material is a component that colors a recording medium and significantly affects the appearance of the recorded matter.

[0034] Examples of the coloring material include various pigments such as organic pigments and inorganic pigments, and various dyes. One or a combination of two or more selected from these may be used.

[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, dioxandinone 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 them, the coloring material preferably contains at least one dye selected from the group consisting of sublimation dyes, oil-based dyes, and disperse dyes.

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

[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, 19 ... 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, 34; CI Solvent Yellow 14, 16, 19, 29, 56, 82; CI Solvent Red 1, 3, 8, 18, 24, 27, 43, 51, 72, 73, 132, 218; CI Solvent Violet 3; CI Solvent Blue 2, 5, 11, 70; CI Solvent Green 3, 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. red dyes such as CI Reactive Violet 24, violet dyes such as CI Reactive Blue 2, 5, 10, 13, 14, 15, 15:1, 21, 49, 63, 71, 72, 75, 162, 176, blue dyes such as CI Reactive Blue 4, 19, 198, green dyes such as CI Reactive Green 5, 8, 19, and black dyes such as CI Reactive Black 1, 8, 23, 39, and the like.

[0044] The lower limit of the content of the coloring material 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 coloring material 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 in the recorded portion of a recorded matter produced using the composition for inkjet, and also makes it possible to more effectively prevent the occurrence of undesired color unevenness in the recorded matter.

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

[0047] However, the proportion of the colorant not contained in the particles to the total colorant 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.

[0048] <1-3> Polyester resin having sulfo group 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 is also referred to as a "sulfo group-containing polyester resin". The sulfo group-containing polyester resin has a function of improving the fixability and fastness of the recorded part in the recorded matter produced using the inkjet composition, and also has a function of improving the texture and touch. It also has a function of enhancing the color development of the coloring material. In addition, since the sulfo group-containing polyester resin has excellent hydrophilicity, it has a function of enhancing the dispersion stability of solid matter in the inkjet composition containing water and the storage stability of the inkjet composition, and as a result, it also has a function of improving the ejection stability of the inkjet composition.

[0049] Polyester is a general term for polymeric materials having ester bonds in the main chain, and generally contains a chemical structure formed by dehydration condensation of a polyol component having multiple hydroxyl groups in its molecule and a polycarboxylic acid component having 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 polyvalent carboxylic 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, in the dicarboxylic acid component, or in 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 the diol component 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, 3-methyl-1,5-pentanediol, diethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, 1,4-cyclohexanediol, and cyclohexanedimethanol; aromatic diols such as 1,4-benzenedimethanol; and compounds in which a sulfo group has been introduced into these. One or more selected from these can be used in combination.

[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 dicarboxylic acid component, but preferably contains a plurality of types of components.

[0055] This enhances the amorphousness of the sulfo group-containing polyester resin, and can suitably prevent crystallization in the composition for inkjet or in the recording part formed using the composition for inkjet, thereby improving the storage stability of the composition for inkjet 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. In addition, for example, the hydrophobicity of the sulfo group-containing polyester resin can be appropriately increased, and even when the composition for inkjet is stored in a high temperature environment, the sulfo group-containing polyester resin can be more effectively prevented from being unintentionally dissolved in a dispersion medium mainly composed of water. In addition, the water resistance of the recorded matter produced using the composition for inkjet can be made more excellent. In addition, when the composition for inkjet contains a dye as a coloring material, the affinity between the sulfo group-containing polyester resin and the coloring material can be made higher, and the color development property is particularly excellent. In addition, the coloring material can be suitably contained in the particles, and the above-mentioned effects are more significantly exhibited.

[0058] Examples of aromatic dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and diphenic acid, and compounds having a sulfo group introduced therein. Among these, terephthalic acid, isophthalic acid, and compounds having a sulfo group introduced therein 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%. 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, and to improve 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. Also, 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, fumaric acid, maleic acid, itaconic acid, hexahydrophthalic acid, tetrahydrophthalic acid, and cyclohexanedicarboxylic acid, as well as compounds having a sulfo group introduced therein.

[0062] When the sulfo group-containing polyester resin contains multiple types of components as dicarboxylic acids, it is preferable that the dicarboxylic acids 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 has the effect that, although different, they have similar structures, they are easily compatible with each other and the amorphousness is enhanced.

[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, for example, by heating a mixture containing an ester compound of a diol component and a dicarboxylic acid component, and further containing a catalyst or other component as necessary. As the ester compound of the dicarboxylic acid component, for example, a methyl ester, an ethyl ester, or the like can be suitably used. In the method for producing such a polyester resin, a component containing a sulfo group can be used as a part of the monomer component to produce a sulfo group-containing polyester resin.

[0066] The sulfo group-containing polyester resin may be synthesized by a method including a first reaction step of heating a mixture containing an ester compound of a diol component and a dicarboxylic acid component, and further containing a catalyst and other components as necessary, followed by a second reaction step of adding a monomer component containing a sulfo group to the reaction system and heating the mixture.

[0067] <1-3-3> Other ingredients The sulfo group-containing polyester resin may have a component other than the diol component and the dicarboxylic acid component described above. Examples of such components include a polyhydric alcohol component having a valence of 3 or more, a polyvalent carboxylic acid component having a valence of 3 or more, a monovalent carboxylic acid component in which a portion of the hydroxyl groups of the diol component is esterified, and a monovalent alcohol component in which a portion of the carboxyl groups of the dicarboxylic acid component is esterified.

[0068] 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.

[0069] The particles constituting the composition for inkjet need only contain at least one type of sulfo group-containing polyester resin, and may contain a plurality of types of sulfo group-containing polyester resins.

[0070] <1-3-4> Other conditions The sulfo group-containing polyester resin preferably satisfies the following conditions.

[0071] The ratio of the number of moles of sulfo groups contained in the sulfo group-containing polyester resin to the number of moles of all constituent monomers of the sulfo group-containing polyester resin, i.e., the X1, may be smaller than the X2, i.e., the ratio of the number of moles of anionic groups contained in the polymer dispersant to the number of moles of all constituent monomers of the polymer dispersant, but it is preferable to satisfy the following condition. That is, the lower limit of X1 is preferably 0.5 mol%, more preferably 0.6 mol%, and even more preferably 0.7 mol%. The upper limit of X1 is preferably 2.5 mol%, more preferably 2.0 mol%, and even more preferably 1.2 mol%.

[0072] This makes it possible to improve the dispersion stability of the particles in the composition for inkjet, the storage stability of the composition for inkjet, and the ejection stability of the composition for inkjet by an inkjet method, while improving the color development of the recorded portion formed using the composition for inkjet. Also, it is possible to improve the water resistance of the recorded portion formed by the composition for inkjet.

[0073] The lower limit of the number average molecular weight of the sulfo group-containing polyester resin is preferably 4,000, more preferably 5,000, and even more preferably 6,000. The upper limit of the number average molecular weight of the sulfo group-containing polyester resin is preferably 20,000, more preferably 15,000, and even more preferably 12,000.

[0074] This makes it possible to ensure sufficiently excellent fixation of the recording portion of the inkjet composition to the recording medium and durability of the recorded matter produced using the inkjet composition, while also improving the dispersion stability of the particles in the inkjet composition, the storage stability of the inkjet composition, and the ejection stability of the inkjet composition by the inkjet method.

[0075] 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.

[0076] 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.

[0077] 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 composition for inkjet at a higher level.

[0078] The lower limit of the content of the sulfo group-containing polyester resin in the composition for inkjet is preferably 3.0% by mass, more preferably 4.0% by mass, and even more preferably 4.5% by mass, and the upper limit of the content of the sulfo group-containing polyester resin in the composition for inkjet is preferably 35.0% by mass, more preferably 30.0% by mass, and even more preferably 28.0% by mass.

[0079] The content of the coloring material in the inkjet composition is X C [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 C The lower limit of X is preferably 3.0, more preferably 3.5, and even more preferably 4.0. P / X CThe upper limit of is preferably 30.0, more preferably 20.0, and even more preferably 15.0.

[0080] This makes it possible to improve the color development of the recorded portion formed using the composition for inkjet. Also, it makes it possible to improve the fixation of the recorded portion to the recording medium, and it makes it possible to more effectively prevent the coloring material from being unintentionally dispersed outside the recorded matter when the recorded matter produced using the composition for inkjet is subjected to a heat treatment such as washing / cleaning with hot water, heating and drying with a dryer, or ironing.

[0081] It is sufficient that the sulfo group-containing polyester resin constituting the composition for inkjet constitutes particles, at least a portion of which contains a colorant, and the composition for inkjet may further contain, for example, particles made of a sulfo group-containing polyester resin that does not contain a colorant.

[0082] 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.

[0083] <1-4> Polymer dispersants with anionic groups The composition for inkjet contains a polymer dispersant having an anionic group. Hereinafter, such a polymer dispersant having an anionic group is also referred to as an "anionic group-containing polymer dispersant". The anionic group-containing polymer dispersant, when used together with the above-mentioned sulfo group-containing polyester resin, has a function of increasing the dispersion stability of solid matter in the composition for inkjet containing water and the storage stability of the composition for inkjet, and as a result, has a function of improving the ejection stability of the composition for inkjet.

[0084] The anionic group-containing polymer dispersant may be any polymer dispersant having an anionic functional group, and the basic skeleton of the anionic group-containing polymer dispersant is not particularly limited, and examples thereof include a polyester skeleton, a (meth)acrylic skeleton, a styrene (meth)acrylic acid skeleton, and a styrene maleic acid skeleton.

[0085] Among these, the anionic group-containing polymer dispersant is preferably one having a polyester skeleton.

[0086] This improves the affinity with the sulfo group-containing polyester resin, and improves the dispersion stability of the solid content in the composition for inkjet, the storage stability of the composition for inkjet, and the ejection stability by the inkjet method.

[0087] When the anionic group-containing polymer dispersant has a polyester skeleton, the constituent monomers of the anionic group-containing polymer dispersant can be those explained in the above <1-3-1> to <1-3-3>.

[0088] The molecular weight of the anionic group-containing polymer dispersant is not particularly limited, but it is preferable that the anionic group-containing polymer dispersant has a number average molecular weight smaller than that of the sulfo group-containing polyester resin.

[0089] This enhances the solubility in water and also suppresses the increase in viscosity due to cross-linking adsorption of the polymer dispersant, further improving the inkjet ejection stability.

[0090] The lower limit of the number average molecular weight of the anionic group-containing polymeric dispersant is preferably 500, more preferably 1,000, and even more preferably 1,500. The upper limit of the number average molecular weight of the anionic group-containing polymeric dispersant is preferably 5,000, more preferably 4,000, and even more preferably 3,000. This makes the above-mentioned effects more pronounced.

[0091] The lower limit of the difference between the number average molecular weight of the sulfo group-containing polyester resin and the number average molecular weight of the anionic group-containing polymeric dispersant is preferably 3,000, more preferably 4,000, and even more preferably 5,000. The upper limit of the difference between the number average molecular weight of the sulfo group-containing polyester resin and the number average molecular weight of the anionic group-containing polymeric dispersant is preferably 15,000, more preferably 11,000, and even more preferably 9,000. This makes the above-mentioned effects more pronounced.

[0092] Examples of the anionic group contained in the anionic-group-containing polymer dispersant include a sulfo group, a carboxyl group, a sulfate ester salt, and a phosphate ester salt, with a sulfo group or a carboxyl group being preferred. This makes the above-mentioned effects more pronounced.

[0093] The ratio of the number of moles of anionic groups contained in the polymer dispersant to the number of moles of all constituent monomers of the polymer dispersant, i.e., the X2, may be larger than the X1, i.e., the ratio of the number of moles of sulfo groups contained in the sulfo group-containing polyester resin to the number of moles of all constituent monomers of the sulfo group-containing polyester resin, but preferably satisfies the following condition. That is, the lower limit of X2 is preferably 3.0 mol%, more preferably 3.5 mol%, and even more preferably 4.0 mol%. The upper limit of X2 is preferably 24.0 mol%, more preferably 20.0 mol%, and even more preferably 16.0 mol%.

[0094] This makes it possible to improve the dispersion stability of the particles in the composition for inkjet, the storage stability of the composition for inkjet, and the ejection stability of the composition for inkjet by an inkjet method, while improving the color development of the recorded portion formed using the composition for inkjet. Also, it is possible to improve the water resistance of the recorded portion formed by the composition for inkjet.

[0095] In particular, when the anionic group-containing polymeric dispersant is a polyester-based polymeric dispersant having a sulfo group as the anionic group, the lower limit of X2 is preferably 4.0 mol%, more preferably 4.3 mol%, and even more preferably 4.5 mol%, and the upper limit of X2 is preferably 7.5 mol%, more preferably 6.5 mol%, and even more preferably 6.0 mol%. This makes the above-mentioned effects more pronounced.

[0096] The lower limit of the content of the anionic group-containing polymer dispersant 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. The upper limit of the content of the anionic group-containing polymer dispersant 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.

[0097] The lower limit of the content of the anionic group-containing polymer dispersant per 100 parts by mass of the sulfo group-containing polyester resin is preferably 5 parts by mass, more preferably 7 parts by mass, and even more preferably 10 parts by mass. The upper limit of the content of the anionic group-containing polymer dispersant per 100 parts by mass of the sulfo group-containing polyester resin is preferably 25 parts by mass, more preferably 22 parts by mass, and even more preferably 20 parts by mass.

[0098] This makes it possible to ensure that the color development, fixation, adhesion strength, etc. of the recording portion formed using the composition for inkjet are sufficiently excellent, while also making it possible to further improve the dispersion stability of the solid content in the composition for inkjet, the storage stability of the composition for inkjet, and the ejection stability by the inkjet method.

[0099] <1-5> Water-soluble organic solvents The composition for inkjet may contain a water-soluble organic solvent.

[0100] This makes it possible, for example, to suitably adjust the viscosity of the composition for inkjet and to enhance the moisture retention of the composition for inkjet, thereby making it possible to more stably eject droplets by the inkjet method.

[0101] Examples of the water-soluble organic solvent contained in the composition for inkjet include glycerin, propylene glycol, and 2-pyrrolidone.

[0102] By including these solvents, the evaporation rate can be slowed down due to excellent moisturizing ability, and more stable droplet ejection can be achieved.

[0103] The lower limit of the content of the water-soluble organic solvent contained in the composition for inkjet is not particularly limited, but is preferably 0 mass%, more preferably 1.0 mass%, and even more preferably 3.0 mass%. The upper limit of the content of the water-soluble organic solvent contained in the composition for inkjet is not particularly limited, but is preferably 30.0 mass%, more preferably 25.0 mass%, and even more preferably 20.0 mass%. This allows the above-mentioned effect of including the water-soluble organic solvent to be more significantly exhibited.

[0104] <1-6> Other ingredients The composition for inkjet may contain components other than the components described above. Hereinafter, in this section, such components are also referred to as "other components".

[0105] Examples of other components include resin materials other than sulfo group-containing polyester resins, various surfactants, dispersants other than anionic group-containing polymer dispersants such as low molecular weight dispersants having no polymer structure, polymer dispersants having no anionic group, 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, fungicides, and rust inhibitors. As the preservatives and fungicides, for example, compounds having an isothiazolin ring structure in the molecule can be suitably used.

[0106] Furthermore, if the composition for inkjet contains a surfactant, the wettability of the composition for inkjet with respect to the recording medium can be made more suitable, which is advantageous in obtaining better image quality.

[0107] As the surfactant contained in the composition for inkjet, for example, various surfactants such as anionic surfactants, cationic surfactants, and nonionic surfactants can be used.

[0108] More specifically, examples of the surfactant contained in the composition for inkjet include acetylene-based surfactants, silicone-based surfactants, and fluorine-based surfactants.

[0109] 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 a plurality of types of components as other components, it is preferable that the total content of these components satisfies the above condition.

[0110] <1-7>Other conditions The lower limit of the viscosity of the composition for inkjet 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. The upper limit of the viscosity of the composition for inkjet at 25° C. is not particularly limited, but is preferably 9.0 mPa·s, more preferably 8.0 mPa·s, and even more preferably 7.0 mPa·s. This further improves the ejection stability of the composition for inkjet.

[0111] The viscosity was measured at 25° C. using a viscoelasticity tester such as MCR-300 manufactured by Pysica, with a shear rate of 10 [s -1 ] to 1000[s -1 ] and reading the viscosity at a Shear Rate of 200.

[0112] The lower limit of the surface tension of the composition for inkjet 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 composition for inkjet 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.

[0113] This makes it more difficult for nozzle clogging of a recording device using the inkjet method to occur, and improves the ejection stability of the inkjet composition. Even if the nozzle is clogged, the nozzle can be capped, i.e., recovery by capping can be improved.

[0114] The surface tension may be a value measured by the Wilhelmy method. The surface tension may be measured using a surface tensiometer such as CBVP-7 manufactured by Kyowa Interface Science Co., Ltd.

[0115] 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 according to 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.

[0116] The lower limit of the average particle size of the particles is not particularly limited, but is preferably 5 nm, more preferably 20 nm, and even more preferably 30 nm, and the upper limit of the average particle size of the particles is not particularly limited, but is preferably 300 nm, more preferably 280 nm, and even more preferably 260 nm.

[0117] This allows the preparation of the composition for inkjet to be easily carried out, and also allows the dispersion stability of the particles in the composition for inkjet, the storage stability of the composition for inkjet, and the ejection stability of the composition for inkjet by an inkjet method to be improved. Also, the color development of the coloring material can be improved.

[0118] In this specification, the average particle size refers to the average particle size on a volume basis unless otherwise specified. The average particle size can be determined, for example, by measurement using a Microtrac UPA (manufactured by Nikkiso Co., Ltd.).

[0119] The lower limit of the content of the particles in the composition for inkjet is preferably 3.2% by mass, more preferably 4.4% by mass, and even more preferably 5.1% by mass, and the upper limit of the content of the particles in the composition for inkjet is preferably 55.0% by mass, more preferably 44.0% by mass, and even more preferably 38.0% by mass.

[0120] This makes it possible to ensure that the color development, fixation, adhesion strength, etc. of the recording portion formed using the composition for inkjet are sufficiently excellent, while also making it possible to further improve the dispersion stability of the solid content in the composition for inkjet, the storage stability of the composition for inkjet, and the ejection stability by the inkjet method.

[0121] <2> Method for producing composition for inkjet recording Next, a method for producing the composition for ink jet will be described. The composition for inkjet of the present invention can be suitably produced, for example, by using a method having an emulsified suspension preparation step of preparing an emulsified suspension by mixing a first composition containing a sulfo group-containing polyester resin, a colorant, an anionic group-containing polymeric dispersant, and an organic solvent with a second composition containing water, and an organic solvent removal step of removing at least a part of the organic solvent from the emulsified suspension.

[0122] In such a method, first, a first composition containing a sulfo group-containing polyester resin, a coloring material, and an organic solvent is prepared.

[0123] The first composition may be prepared by mixing the respective components simultaneously, or may be prepared by mixing the respective components in two or more separate stages.

[0124] As the organic solvent, for example, one having a solubility in water at 25° C. of 0.1 g / 100 gH2O or more and 30 g / 100 gH2O or less can be suitably used.

[0125] Examples of such organic solvents include 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 may be used in combination.

[0126] 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 is preferably an organic solvent with a relatively low boiling point.

[0127] From this viewpoint, the organic solvent is preferably methyl ethyl ketone or ethyl acetate, and more preferably methyl ethyl ketone.

[0128] In addition, components other than the sulfo group-containing polyester resin, the coloring material, and the organic solvent may be used in the preparation of the first composition. Such components include, for example, basic compounds, emulsifiers, and the like.

[0129] <2-1> 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.

[0130] The emulsified suspension thus obtained is in a state where a dispersoid containing a sulfo group-containing polyester resin, a coloring material, an anionic group-containing polymeric dispersant and an organic solvent is dispersed in an aqueous dispersion medium.

[0131] The second composition may contain at least water, and may be, for example, pure water or a liquid containing components other than water. Examples of such components include an organic solvent that is more soluble in water than the organic solvent used in preparing the first composition, and a basic component.

[0132] Examples of organic solvents having a higher solubility in water than the organic solvent used in the preparation of the first composition include organic solvents that are miscible with water in any ratio, such as 2-propanol.

[0133] The basic component may, for example, be mixed with the first composition prior to mixing the first composition with the second composition.

[0134] Examples of basic compounds include inorganic bases such as sodium hydroxide, potassium hydroxide, and ammonia, and organic bases such as diethylamine, triethylamine, and isopropylamine. One or more selected from these can be used in combination.

[0135] 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 dropping the second composition onto 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 as described above.

[0136] Moreover, 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 as described above.

[0137] <2-2> Organic solvent removal process In the organic solvent removing step, at least a portion of the organic solvent is removed from the emulsified suspension.

[0138] As a result, solid particles containing a coloring material and a sulfo group-containing polyester resin are formed, which correspond to the particles constituting the composition for inkjet of the present invention.

[0139] 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.

[0140] 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 it is, or the dispersion may be mixed with other components to form the inkjet composition of the present invention.

[0141] 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.

[0142] 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, and then stirring and dispersing the microparticle cake in water, and further dehydrating the same.

[0143] After dehydration, a drying treatment may be carried out, if necessary. For the drying process, for example, a mixing vacuum dryer such as a Ribocone type dryer (manufactured by Okawara Manufacturing Co., Ltd.) or a Nauta Mixer (manufactured by Hosokawa Micron Corporation), or a fluidized bed type dryer such as a fluidized bed dryer (manufactured by Okawara Manufacturing Co., Ltd.) or a vibration fluidized bed dryer (manufactured by Chuo Kakoki Co., Ltd.) can be used.

[0144] When the dehydration and drying treatments are carried out, the washed particles are mixed with other components containing at least water, whereby the above-mentioned composition for inkjet of the present invention can be obtained.

[0145] In the organic solvent removal step, it is sufficient to remove at least a part of the organic solvent contained in the emulsion suspension, particularly the organic solvent contained in the dispersoid of the emulsion suspension, and it is not necessary to remove it completely. Even in such a case, the remaining organic solvent can usually be sufficiently removed by a post-treatment step such as washing or drying. In addition, a small amount of the organic solvent may remain in the finally obtained composition for inkjet.

[0146] <3> Inkjet recording method Next, the ink jet recording method of the present invention will be described.

[0147] The inkjet recording method of the present invention has a discharge step of discharging the inkjet composition of the present invention by an inkjet method.

[0148] This makes it possible to provide an inkjet recording method that can stably eject droplets by the inkjet method and is suitable for producing a recorded matter having a recording part with excellent color development. In particular, it is possible to exhibit excellent color development on various recording media. In addition, it is possible to provide excellent fixability and adhesion strength of the recording part formed using the inkjet composition.

[0149] 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 is attached. This further improves the color development of the recorded portion and the fixation of the recorded portion to the recording medium.

[0150] <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 an ejection method, a piezoelectric method, a method of ejecting ink by bubbles generated by heating the ink, and the like can be used. Among them, the piezoelectric method is preferred from the viewpoint of the resistance to deterioration of the inkjet composition, etc.

[0151] 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 color materials may be used in combination.

[0152] In the ejection step, an ink other than the ink-jet composition according to the present invention may be used in combination.

[0153] <3-2> Recording media The constituent material of the recording medium is not particularly limited, but examples thereof include resin materials such as polyurethane, polyethylene, polypropylene, polyester, polyamide, and acrylic resin, paper such as cardboard, plain paper, and paper for inkjet printing, glass, metal, ceramics, leather, wood, pottery, and concrete, and fibers composed of at least one of these materials, various natural fibers such as silk, wool, cotton, hemp, polyester, polyamide (nylon), acrylic, polyurethane, cellulose, linter, rayon, cupra, and acetate, synthetic fibers, and semi-synthetic fibers, and one or more selected from these materials can be used in combination. In addition, the recording medium may be one having a three-dimensional shape such as a sheet, a sphere, or a rectangular parallelepiped shape.

[0154] When the recording medium is made of a material containing polyester, the adhesion between the recording medium and the recording portion formed by the inkjet composition of the present invention can be made more excellent.

[0155] In particular, the recording medium is preferably 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, a recorded matter in which a recorded portion is provided on such fabric is required to have a texture, particularly smoothness, suppleness, softness, and durability of the recorded portion. The present invention can meet such requirements. Therefore, when the recording medium is fabric, the effect of the present invention is more pronounced.

[0156] As the fabric, various woven fabrics such as plain weave, twill weave, satin weave, varied plain weave, varied twill weave, varied satin weave, variegated weave, patterned weave, single layer weave, double weave, multi-weave, warp pile weave, weft pile weave, and leno weave can be used.

[0157] The thickness of the fibers constituting the fabric can be, for example, 10d or more and 100d or less.

[0158] Examples of fibers constituting the fabric 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.

[0159] In addition, 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, excellent texture, excellent elasticity, and excellent adhesion to the recording medium.

[0160] <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.

[0161] 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.

[0162] This allows the effect of providing the heating step as described above to be more prominently exhibited. Also, the energy required for the production of the recorded matter can be reduced, and the productivity of the recorded matter can be further improved. Also, recording media with relatively low heat resistance can be suitably applied, and the range of recording media selection can be further expanded. Also, it is possible to suitably prevent unintended discoloration, changes in optical density, etc. caused by heating after the production of the recorded matter, for example, washing / cleaning with hot water, heating and drying with a dryer, ironing, and other heating treatments. Also, when the heating temperature in this step is within the above range, it is possible to more effectively prevent the texture of the recorded part from deteriorating.

[0163] 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. 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.

[0164] This allows the effect of providing the heating step as described above to be more prominently exhibited. Also, the energy required for the production of the recorded matter can be reduced, and the productivity of the recorded matter can be further improved. Also, recording media with relatively low heat resistance can be suitably applied, and the range of recording media selection can be further expanded. Also, it is possible to suitably prevent unintended discoloration, changes in optical density, etc. caused by heating after the production of the recorded matter, for example, washing / cleaning with hot water, heating and drying with a dryer, ironing, and other heating treatments. Also, when the heating temperature in this step is within the above range, it is possible to more effectively prevent the texture of the recorded part from deteriorating.

[0165] In addition, this process may be carried out by heating the surface of the recording medium to which the inkjet composition is adhered while being separated from a heating member, or by heating the recording medium to which the inkjet composition is adhered while being in close contact with a heating member.

[0166] The heating step may be performed 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 the inkjet composition may be heated after contacting the recording medium. In this case, for example, heating may be performed continuously before and after application of the inkjet composition to the recording medium, or heating of the recording medium to which the inkjet composition is applied may be interrupted and then resumed.

[0167] <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.

[0168] In the following description, an on-carriage type printer in which ink cartridges are mounted on a carriage is taken 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.

[0169] 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 with the movement of the carriage to eject droplets onto the recording medium. In the present invention, the recording device is not limited to a serial printer, and may 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.

[0170] In the drawings used in the following description, the scale of each component has been appropriately changed so that each component is of a recognizable size.

[0171] 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 performs the inkjet recording method of the present invention described above.

[0172] This makes it possible to provide a recording device that has a recording section with excellent texture and is capable of suitably producing recorded matter with excellent durability.

[0173] In particular, the recording apparatus 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 feed mechanism 8, a guide rod 9, a linear encoder 10, and a control unit CONT.

[0174] The control unit CONT controls the operation of the entire recording apparatus 1 . The carriage 4 carries the inkjet head 2, which will be described later, and also detachably mounts an ink cartridge 3, which supplies a composition for inkjet to the inkjet head 2.

[0175] The platen 5 is disposed below the inkjet head 2, and the recording medium M is transported across the platen 5.

[0176] 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.

[0177] The carriage movement mechanism 7 moves the carriage 4 in the width direction of the recording medium M. The medium feed mechanism 8 transports the recording medium M in a medium feed direction. Here, the medium width direction is the main scanning direction, which is the scanning direction of the inkjet head 2. The medium feed direction is a direction perpendicular to the main scanning direction, and is the sub-scanning direction in which the recording medium M moves.

[0178] The inkjet head 2 is a means for depositing the inkjet composition on 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 deposited. These nozzles are arranged in a row, and a nozzle surface is formed on the surface of the nozzle plate.

[0179] As a method for ejecting the inkjet composition from a nozzle, for example, a piezoelectric method can be mentioned in which pressure and a recording information signal are simultaneously applied to the inkjet composition by a piezoelectric element to eject and record droplets of the inkjet composition.

[0180] In Fig. 1, the ink cartridge 3 that supplies the inkjet composition to the inkjet head 2 is composed of four independent cartridges. For example, each of the four cartridges is filled with a different type of inkjet composition. The ink cartridge 3 is detachably mounted on the inkjet head 2. In the example of Fig. 1, the number of cartridges is four, but this is not limiting and any desired number of cartridges can be mounted.

[0181] The carriage 4 is attached in a state 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 moving mechanism 7. In the example of Fig. 1, the carriage 4 moves in the main scanning direction, but is not limited to this, and may move in the sub-scanning direction in addition to the movement in the main scanning direction.

[0182] The installation position of the heating mechanism 6 is not particularly limited as long as it is provided at 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, the position on the recording medium M where the composition for inkjet is attached can be reliably heated, and the composition for inkjet attached to the recording medium M can be efficiently dried.

[0183] 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 at around 2,450 MHz, and a dryer mechanism that blows warm air.

[0184] The control of 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.

[0185] 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 attached to the recording medium M. Any of the mechanisms described for the heating mechanism 6 can be used as the second heating mechanism.

[0186] The linear encoder 10 detects the position of the carriage 4 in the main scanning direction with 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 moving speed of the carriage 4.

[0187] <5> Recordings Next, the recorded matter according to the present invention will be described.

[0188] The recorded matter according to the present invention has a recorded portion formed using the inkjet composition according to the present invention described above.

[0189] This makes it possible to provide a recorded matter having a recorded portion with excellent color development, and also makes it possible to provide excellent fixation and adhesion strength of the recorded portion to the recording medium. As the recording medium, the above-mentioned ones can be suitably used.

[0190] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these.

[0191] For example, the composition for inkjet 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.

[0192] Furthermore, for example, the present invention may be applied to a method having other steps in addition to the steps described above.

[0193] In this case, the pretreatment step may be, for example, a step of applying a coating layer to the recording medium.

[0194] An example of the intermediate processing step is a step of preheating the recording medium. Moreover, the post-processing step may be, for example, a step of cleaning the recording medium.

[0195] The composition for inkjet of the present invention may be produced by any method, and is not limited to the method described above. For example, the composition for inkjet of the present invention may contain particles formed by an emulsion polymerization method. EXAMPLES

[0196] Next, specific examples of the present invention will be described. <6> Synthesis of polyester resin (Synthesis Example A1) An autoclave equipped with a thermometer and a stirrer was charged with 100.0 parts by mass of dimethyl terephthalate, 100.0 parts by mass of dimethyl isophthalate, 8.0 parts by mass of dimethyl monosodium 5-sulfoisophthalate, 90.0 parts by mass of ethylene glycol, 45.0 parts by mass of 1,3-propanediol, and 0.5 parts by mass of tetrabutoxytitanate, and the mixture was heated at 150 to 200°C for 180 minutes to carry out an ester exchange reaction.

[0197] Next, at a temperature of 200°C, the pressure of the system was gradually reduced to 10 mmHg after 30 minutes while distilling off the diol component, and then the temperature was gradually increased from 200°C to 240°C while continuing vacuum heating for 120 minutes to obtain a sulfo group-containing polyester resin.

[0198] The obtained sulfo group-containing polyester resin had a number average molecular weight of 7,500, a composition ratio, in molar ratio, of terephthalic acid unit / isophthalic acid unit / 5-sulfoisophthalic acid sodium salt unit / ethylene glycol unit / 1,3-propanediol unit=24.0:25.0:1.0:26.0:24.0, a glass transition point of 65°C, and a proportion X1 of sulfo groups to all monomer units of 1.0 mol%.

[0199] (Synthesis examples A2 to A9) A sulfo group-containing polyester resin was obtained in the same manner as in Synthesis Example A1, except that the types and ratios of monomer components used as raw materials and the polymerization heating conditions were adjusted.

[0200] (Synthesis Example A10) A polyester resin was obtained in the same manner as in Synthesis Example A1, except that the types and ratios of monomer components used as raw materials and the polymerization heating conditions were adjusted. The polyester resin thus obtained did not have a sulfo group in the molecule.

[0201] The conditions of the polyester resins obtained in the synthesis examples A1 to A10 are summarized in Table 1. In the table, dimethyl terephthalate is indicated as "TPA", dimethyl isophthalate as "IPA", 5-dimethyl monosodium sulfoisophthalate as "5S-IPA", ethylene glycol as "EG", neopentyl glycol as "NPG", 1,3-propanediol as "1,3-PD", 1,4-cyclohexanediol as "1,4-CHD", and 3-methyl-1,5-pentanediol as "MPD". The sulfo group-containing polyester resins contained in the compositions for inkjet of the synthesis examples A1 to A9 all had acid values ​​in the range of 1.0 KOHmg / g or more and 15 KOHmg / g or less.

[0202] [Table 1]

[0203] <7> Synthesis of polymer dispersants (Synthesis Example B1) An autoclave equipped with a thermometer and a stirrer was charged with 100.0 parts by mass of dimethyl terephthalate, 100.0 parts by mass of dimethyl isophthalate, 40.0 parts by mass of dimethyl monosodium 5-sulfoisophthalate, 90.0 parts by mass of ethylene glycol, 50.0 parts by mass of 1,3-propanediol, and 0.5 parts by mass of tetrabutoxytitanate, and the mixture was heated at 150 to 200°C for 180 minutes to carry out an ester exchange reaction.

[0204] Next, at a temperature of 180°C, the pressure of the system was gradually reduced to 10 mmHg after 30 minutes while distilling off the diol component, and then the temperature was gradually increased from 180°C to 200°C while continuing vacuum heating for 120 minutes to obtain an anionic group-containing polymer dispersant.

[0205] The obtained anionic group-containing polymeric dispersant had a number average molecular weight of 1,500, a composition ratio, in molar ratio, of terephthalic acid unit / isophthalic acid unit / 5-sulfoisophthalic acid sodium salt unit / ethylene glycol unit / 1,3-propanediol unit=22.0:22.0:6.0:28.0:22.0, a glass transition point of 56°C, and a proportion X2 of the anionic group to all monomer units of 6.0 mol%.

[0206] (Synthesis examples B2~B6) An anionic group-containing polymeric dispersant was obtained in the same manner as in Synthesis Example B1, except that the types and ratios of monomer components used as raw materials and the polymerization heating conditions were adjusted.

[0207] (Synthesis Example B7) Into an autoclave equipped with a thermometer and a stirrer, 100.0 parts by mass of dimethyl terephthalate, 100.0 parts by mass of dimethyl isophthalate, 90.0 parts by mass of ethylene glycol, 45.0 parts by mass of 1,3-propanediol, and 0.5 parts by mass of tetrabutoxytitanate were charged, and the mixture was heated at 150 to 200°C for 180 minutes to carry out an ester exchange reaction.

[0208] Next, at a temperature of 200°C, the pressure of the system was gradually reduced to 10 mmHg after 30 minutes while distilling off the diol component, and then the temperature was gradually raised from 200°C to 210°C while continuing vacuum heating for 120 minutes to obtain a hydroxyl-terminated polyester resin having a number average molecular weight of 2,800, a hydroxyl value of 40.0, and an acid value of less than 2. The obtained hydroxyl-terminated polyester resin was melted under a nitrogen atmosphere, and then 7.0 parts by mass of trimellitic anhydride was added and subjected to an addition reaction at 200°C for about 30 minutes to obtain a carboxylic acid group-containing polyester resin having a number average molecular weight of 2,800, an acid value of 80.0, and a hydroxyl value of less than 2. The composition ratio, in molar ratio, was terephthalic acid unit / isophthalic acid unit / trimellitic acid unit / ethylene glycol unit / 1,3-propanediol unit=23.0:23.0:8.0:24.0:22.0, the glass transition point was 61° C., and the proportion X2 of anionic groups to all monomer units was 16.0 mol %.

[0209] (Synthesis example B8) In a reaction vessel equipped with a reflux condenser and a thermometer, 73.0 parts by mass of styrene (manufactured by Tokyo Chemical Industry Co., Ltd.), 15.0 parts by mass of methyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 10.8 parts by mass of acrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), and 10.0 parts by mass of 3-mercaptopropionic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to make a total of 270 parts by mass of toluene (manufactured by Tokyo Chemical Industry Co., Ltd.), and dissolved using a magnetic stirrer. After replacing the inside of the reactor with nitrogen, 30 parts by mass of a toluene solution of 1.0 part by mass of azobisisobutyronitrile (manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.) was dropped at room temperature. Then, the reaction was carried out at 75 ° C for 6 hours. After the reaction was completed, the reactant was dropped into water to precipitate a white solid. The white solid was suction filtered, washed repeatedly with water, and vacuum dried at 50 ° C for 10 hours to obtain a styrene acrylic acid resin. This styrene-acrylic acid resin had a number average molecular weight of 3,800, an acid value of 84.0, and a composition ratio, in molar ratio, of styrene unit / methyl methacrylate unit / acrylic acid unit=70.0:15.0:15.0, and the proportion X2 of carboxylic acid groups to all monomer units was 15.0 mol %.

[0210] The conditions of the polymer dispersants obtained in the above Synthesis Examples B1 to B8 are summarized in Table 2. In the table, dimethyl terephthalate is indicated as "TPA", dimethyl isophthalate as "IPA", 5-dimethyl monosodium sulfoisophthalate as "5S-IPA", ethylene glycol as "EG", neopentyl glycol as "NPG", 1,3-propanediol as "1,3-PD", 1,4-cyclohexanediol as "1,4-CHD", 3-methyl-1,5-pentanediol as "MPD", trimellitic acid as "TMA", styrene as "ST", acrylic acid as "AA", and methacrylic acid as "MAA".

[0211] [Table 2]

[0212] <8> Preparation of Inkjet Composition Example 1 15.0 parts by mass of CI Disperse Red 60, a disperse dye used as a coloring material, 85.0 parts by mass of the polyester resin synthesized in Synthesis Example A1, 15.0 parts by mass of the polymer dispersant synthesized in Synthesis Example B1, and 385.0 parts by mass of methyl ethyl ketone were mixed and dissolved by stirring while heating at 65°C to 75°C.

[0213] Thereafter, 15 parts by mass of 2-propanol and 485 parts by mass of water were added thereto, and the mixture was heated and stirred at 80°C for 2 hours. Thereafter, the methyl ethyl ketone, 2-propanol, and a portion of the water were distilled off under reduced pressure to obtain an aqueous dispersion having a total content of particles in which the disperse dye was dissolved and fixed in the polyester resin and the polymer dispersant of 30% by mass.

[0214] To 90.0 parts by mass of this aqueous dispersion, 6.0 parts by mass of propylene glycol, 0.2 parts by mass of triethanolamine, 1.0 parts by mass of Olfine E1010 (manufactured by Nissin Chemical Industry Co., Ltd.) as a surfactant, and 2.8 parts by mass of pure water were added and stirred to produce a composition for inkjet printing.

[0215] (Examples 2 to 15) The inkjet compositions were prepared in the same manner as in Example 1, except that the type and amount of the polyester resin, the amount of the colorant, and the type and amount of the polymer dispersant used in preparing the aqueous dispersion were configured as shown in Tables 3 and 4.

[0216] (Comparative Examples 1 to 4) A composition for inkjet was prepared in the same manner as in Example 1, except that the type and amount of polyester resin, the amount of colorant, and the type and amount of polymer dispersant used in the preparation of the above aqueous dispersion were configured as shown in Table 4.

[0217] The types and amounts of polyester resins, colorants, and polymer dispersants used in preparing the aqueous dispersions in the production of the compositions for inkjet in the Examples and Comparative Examples are summarized in Tables 3 and 4. In the tables, the sulfo group-containing polyester resin synthesized in Synthesis Example A1 is designated "A1", the sulfo group-containing polyester resin synthesized in Synthesis Example A2 is designated "A2", the sulfo group-containing polyester resin synthesized in Synthesis Example A3 is designated "A3", the sulfo group-containing polyester resin synthesized in Synthesis Example A4 is designated "A4", the sulfo group-containing polyester resin synthesized in Synthesis Example A5 is designated "A5", the sulfo group-containing polyester resin synthesized in Synthesis Example A6 is designated "A6", the sulfo group-containing polyester resin synthesized in Synthesis Example A7 is designated "A7", the sulfo group-containing polyester resin synthesized in Synthesis Example A8 is designated "A8", the sulfo group-containing polyester resin synthesized in Synthesis Example A9 is designated "A9", the sulfo group-containing polyester resin synthesized in Synthesis Example A10 is designated "A1", the sulfo group-containing polyester resin synthesized in Synthesis Example A11 is designated "A2", the sulfo group-containing polyester resin synthesized in Synthesis Example A12 is designated "A3", the sulfo group-containing polyester resin synthesized in Synthesis Example A13 is designated "A4", the sulfo group-containing polyester resin synthesized in Synthesis Example A14 is designated "A5", the sulfo group-containing polyester resin synthesized in Synthesis Example A15 is designated "A6", the sulfo group-containing polyester resin synthesized in Synthesis Example A16 is designated "A7", the sulfo group-containing polyester resin synthesized in Synthesis Example A17 is designated "A8", the sulfo group-containing polyester resin synthesized in Synthesis Example A18 is designated "A9", the sulfo group-containing polyester resin synthesized in Synthesis Example A19 is designated "A10", the sulfo group-containing polyester resin synthesized in Synthesis Example A10 is designated "A1", the sulfo group-containing polyester resin synthesized in Synthesis Example A11 is designated "A1", the sulfo group-containing polyester resin synthesized in Synthesis Example A12 is designated "A1", the sulf The polyester resin synthesized in Synthesis Example B1 was designated "A10", the anionic group-containing polymer dispersant synthesized in Synthesis Example B1 was designated "B1", the anionic group-containing polymer dispersant synthesized in Synthesis Example B2 was designated "B2", the anionic group-containing polymer dispersant synthesized in Synthesis Example B3 was designated "B3", the anionic group-containing polymer dispersant synthesized in Synthesis Example B4 was designated "B4", the anionic group-containing polymer dispersant synthesized in Synthesis Example B5 was designated "B5", the anionic group-containing polymer dispersant synthesized in Synthesis Example B6 was designated "B6", the anionic group-containing polymer dispersant synthesized in Synthesis Example B7 was designated "B7", the anionic group-containing polymer dispersant synthesized in Synthesis Example B8 was designated "B8", and CI Disperse Red 60 was designated "DR60". The inkjet compositions of the above examples all had a viscosity of 2.0 mPa·s or more and 9.0 mPa·s or less. The viscosity was measured using a viscoelasticity tester MCR-300 (manufactured by Pysica) at 25°C and a shear rate of 10 [s -1 ] to 1000[s -1] and reading the viscosity at a shear rate of 200. The inkjet compositions of the respective examples had a surface tension of 23 mN / m or more and 30 mN / m or less. The surface tension was measured by the Wilhelmy method at 25°C using a surface tensiometer (Kyowa Interface Science Co., Ltd., CBVP-7). The average particle size of the particles containing the colorant and the sulfo group-containing polyester resin in the inkjet compositions of the respective examples was 30 nm or more and 300 nm or less. In the inkjet compositions of the respective examples, the presence of the colorant and the sulfo group-containing polyester resin outside the particles was not confirmed.

[0218] [Table 3]

[0219] [Table 4]

[0220] <9> evaluation <9-1>Dispersion stability For each of the inkjet compositions of the Examples and Comparative Examples, the average particle size of the particles contained in the inkjet composition immediately after production was compared with the average particle size of the particles contained in the inkjet composition after thermal storage in which the inkjet composition was left to stand in a thermo-hygrostat set at 60°C for 5 days, and the results were evaluated according to the following criteria. The smaller the variation in the average particle size, the better the dispersion stability. A grade of B or higher was determined to be good. For particle size measurement, a zeta potential / particle size measurement device ELSZ-1000 manufactured by Otsuka Electronics Co., Ltd. was used.

[0221] A: The increase in ink particle size (D50%) after heat storage is less than 2.5% B: The increase in ink particle size (D50%) after heat storage is 2.5% or more and less than 5% C: The increase in ink particle size (D50%) after heat storage is 5% or more and less than 7.5% D: The increase in ink particle size (D50%) after heat storage is 7.5% or more and less than 10% E: The increase in ink particle size (D50%) after heat storage is 10% or more.

[0222] <9-2> Color development The inkjet compositions of each of the Examples and Comparative Examples were placed in a cartridge for a recording apparatus PX-M860F (manufactured by Seiko Epson Corporation) and set in the recording apparatus, and ejected in a predetermined pattern using high-quality paper as a recording medium.

[0223] The color development property of each of the obtained recorded materials was evaluated. Specifically, the chromaticity of the portion to which the inkjet composition was applied during the manufacturing process of each of the recorded materials was measured using i1 (manufactured by X-rite), and the L * a * b * The color was measured in a color space, and the OD value of the portion of each recorded material to which the inkjet composition was applied was determined and evaluated according to the following criteria. * The higher the value, the better the color development. Grades B and above were considered to be good.

[0224] A:a * is 75 or more and the OD value is 1.0 or more. B:a * is 65 or more and less than 75, and the OD value is 1.0 or more. C:a * is greater than or equal to 55 and less than 65, and the OD value is greater than or equal to 1.0. D:a * is greater than or equal to 0 and less than 55, and the OD value is greater than or equal to 1.0. E:a * is greater than or equal to 0 and less than 55, and the OD value is less than 1.0. The above evaluation results are summarized in Table 5.

[0225] [Table 5]

[0226] As is clear from Table 5, excellent results were obtained in the present invention. In contrast, satisfactory results were not obtained in each of the comparative examples.

[0227] Except for changing the coloring material to CI Solvent Blue 5, an oil-based dye, inkjet compositions were produced in the same manner as in each of the Examples and Comparative Examples, and the inkjet compositions were evaluated in the same manner as in <9-2> above, with the same results as above. In addition, a PX-M860F (manufactured by Seiko Epson Corporation) was used as a recording device, and a cotton cloth was used as a 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 with an iron as a heating member, and the recorded matter was evaluated in the same manner as in <9-2> above, with the same results as above. Furthermore, except for changing the heating temperature in the heating step to within a range of 100°C or more and 160°C or less, and changing the heating time to within a range of 0.2 seconds or more and 300 seconds or less, a recorded matter was produced in the same manner as above, and the same evaluation as in <9-2> above was performed, with the same results as above. [Explanation of symbols]

[0228] REFERENCE SIGNS LIST 1...recording device, 2...inkjet head, 3...ink cartridge, 4...carriage, 5...platen, 6...heating mechanism, 7...carriage moving mechanism, 8...medium feeding mechanism, 9...guide rod, 10...linear encoder, M...recording medium, CONT...control unit

Claims

1. The ink contains water, a polyester resin having a sulfo group, a colorant, and a polymer dispersant having an anionic group, the color material is contained in particles made of a material containing the polyester resin, a ratio X1 [mol %] of the sulfo group to all constituent monomers of the polyester resin is smaller than a ratio X2 [mol %] of the anionic group to all constituent monomers of the polymer dispersant.

2. The composition for inkjet according to claim 1 , wherein the coloring material comprises at least one selected from the group consisting of sublimation dyes, oil-based dyes, and disperse dyes.

3. The composition for ink jet according to claim 1 or 2, wherein the number average molecular weight of the polyester resin is 4,000 or more and 20,000 or less.

4. The composition for inkjet according to claim 1 , wherein X1 is 0.5 mol % or more and 2.5 mol % or less.

5. The composition for ink jet according to claim 1 , wherein the anionic group is a sulfo group or a carboxyl group.

6. The composition for ink jet according to claim 1 , wherein the number average molecular weight of the polymer dispersant is smaller than the number average molecular weight of the polyester resin.

7. The composition for inkjet according to claim 1 , wherein the content of the polymer dispersant relative to 100 parts by mass of the polyester resin is 5 parts by mass or more and 25 parts by mass or less.

8. the polymer dispersant is a polyester-based polymer dispersant having a sulfo group as the anionic group, The composition for ink jet according to claim 1 , wherein X2 is from 4.0 mol % to 7.5 mol %.

9. An ink-jet recording method, comprising a step of ejecting the ink-jet composition according to claim 1 by an ink-jet method.

10. The inkjet recording method according to claim 9, further comprising, after the ejection step, a heating step of heating the recording medium to which the inkjet composition is attached.

11. The inkjet recording method according to claim 10, wherein the heating temperature of the recording medium in the heating step is 100° C. or more and 160° C. or less.

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