Water-based ink for inkjet recording, ink set, inkjet recording device, and image forming method.

Abstract

This technology provides suitable color development, high wash fastness, and abrasion fastness. [Solution] An inkjet water-based ink is used to form an image on a fabric material. The inkjet water-based ink comprises a pigment, a binder, a crosslinking agent, and wax particles. The binder contains an acrylic resin. The crosslinking agent contains at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound. The ratio of the crosslinking agent content to the total amount of the binder, crosslinking agent, and wax particles is 0.05 or more. The wax particles are anionic.

Description

Technical Field

[0001] This specification discloses technologies relating to water-based inks for inkjet recording, ink sets, inkjet recording apparatuses, and image forming methods. This specification particularly discloses technologies relating to water-based inks and the like that can be used for textile printing on fabric materials.

Background Art

[0002] Patent Document 1 discloses a water-based ink for inkjet recording used for textile printing on fabrics. This water-based ink contains a pigment, a water-dispersible resin, and a crosslinking agent.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In image formation using a water-based ink containing a pigment, the pigment adheres to the surface of the fabric material, so washing fastness and rubbing fastness tend to be low. It is also generally known that water-based inks containing pigments have lower color developability than water-based inks containing dyes. Technologies have been developed to improve the washing fastness and rubbing fastness of water-based inks containing pigments by using a binder and a crosslinking agent in combination. However, it is difficult to achieve the required levels of color developability, washing fastness, and rubbing fastness in water-based inks containing pigments. This specification provides a technology that can achieve favorable color developability as well as high washing fastness and rubbing fastness.

Means for Solving the Problems

[0005] The aqueous inkjet recording ink disclosed herein is used to form an image on a fabric. The aqueous inkjet recording ink comprises a pigment, a binder, a crosslinking agent, and wax particles. The binder contains an acrylic resin. The crosslinking agent contains at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound. The ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.05 or more. The wax particles are anionic.

[0006] Before image formation with water-based inkjet recording ink, a pretreatment solution may be applied to the fabric material. Generally, the pretreatment solution is cationic, so the surface of the pretreated fabric material becomes positively charged. The wax particles contained in the above-mentioned water-based inkjet recording ink are anionic. Therefore, when the water-based ink containing these wax particles is applied to the surface of the pretreated fabric material, the presence of positive charges causes interactions between the wax particles, which can cause them to aggregate. The presence of these aggregated wax particles on the surface of the fabric material inhibits the penetration of the pigment in the thickness direction of the fabric material, allowing the pigment to remain on the surface of the fabric material. As a result, it is believed that the color development of the water-based inkjet recording ink can be improved. Furthermore, in the above-mentioned water-based inkjet recording ink, the crosslinking agent containing the above-mentioned compound suitably crosslinks the binder containing the acrylic resin, forming a strong resin coating film. This resin coating film allows the pigment to be fixed to the fabric material, thus providing good wash fastness. In addition, some of the wax particles present in the resin coating film are distributed to cover the surface of the resin coating film, which is believed to improve the friction fastness of the resin coating film. As a result of diligent research by the inventors, it was found that by adjusting the ratio of the crosslinking agent content to the total amount of binder, crosslinking agent, and wax particles to 0.05 or higher, suitable color development, high wash fastness, and abrasion fastness can be achieved through the mechanism described above.

[0007] The ink set is also novel and useful. The ink set comprises the above-mentioned water-based inkjet recording ink and a cationic pretreatment liquid. The cationic pretreatment liquid is applied to the fabric material before forming an image on the fabric material using the water-based inkjet recording ink.

[0008] The inkjet recording device is also novel and useful. The inkjet recording device comprises an ink storage section, an ink ejection section, and an aqueous inkjet recording ink stored in the ink storage section. The inkjet recording device ejects the aqueous inkjet recording ink from the ink ejection section to form an image on a fabric material. The aqueous inkjet recording ink comprises a pigment, a binder, a crosslinking agent, and wax particles. The binder contains an acrylic resin. The crosslinking agent contains at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound. The ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.05 or more. The wax particles are anionic.

[0009] A novel and useful image forming method is also provided for forming an image on a fabric material using an inkjet recording method. This image forming method comprises a pretreatment step, an image forming step, and a drying step. In the pretreatment step, a cationic pretreatment liquid is applied to the fabric material. The pretreatment liquid is applied to the area where an image is formed by an aqueous inkjet recording ink. In the image forming step, an image is formed on the pretreated fabric material using the aqueous inkjet recording ink. In the drying step, the aqueous inkjet recording ink is dried by heating the fabric material on which the image has been formed. The aqueous inkjet recording ink comprises a pigment, a binder, a crosslinking agent, and wax particles. The binder contains an acrylic resin. The crosslinking agent contains at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound. The ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.05 or more. The wax particles are anionic. [Brief explanation of the drawing]

[0010] [Figure 1] This shows the configuration of an inkjet recording device. [Figure 2] This shows a schematic configuration of the discharge head mounted on the carriage. [Figure 3] This shows an example of a configuration in which a pretreatment solution is applied before image formation by an inkjet recording device. [Modes for carrying out the invention]

[0011] (Water-based ink for inkjet recording) Hereinafter, an embodiment of the water-based inkjet recording ink disclosed herein will be described. Hereinafter, the water-based inkjet recording ink may be simply referred to as water-based ink. The water-based ink is used to form an image on a fabric material. Examples of fabric materials include woven fabrics, nonwoven fabrics, knitted fabrics, etc., composed of fiber materials. Examples of fiber materials include natural fibers and synthetic fibers. Examples of natural fibers include cotton, linen, wool, silk, etc. Examples of synthetic fibers include rayon, vinylon, nylon, acrylic, polyurethane, polyester, or acetate, etc. The fabric material may be a blended woven fabric or blended nonwoven fabric using two or more types selected from these. The water-based ink comprises a pigment, a binder, a crosslinking agent, and wax particles.

[0012] (Pigment) The pigments are not particularly limited and include, for example, carbon black, inorganic pigments, and organic pigments. Examples of carbon black include furnace black, lamp black, acetylene black, and channel black. Examples of inorganic pigments include titanium dioxide, iron oxide-based inorganic pigments, and carbon black-based inorganic pigments. 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 perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; dye lake pigments such as basic dye-type lake pigments and acid dye-type lake pigments; nitro pigments: nitroso pigments; aniline black daylight fluorescent pigment; and others. In addition, other pigments can be used as long as they are dispersible in the aqueous phase. Specific examples of these pigments include, for example, CI Pigment Black 1, 6 and 7; CI Pigment Yellow 1, 2, 3, 12, 13, 14, 15, 16, 17, 55, 74, 78, 150, 151, 154, 155, 180, 185 and 194; CI Pigment Orange 31 and 43; CI Pigment Red 2, 3, 5, 6, 7, 12, 15, 16, 48, 48:1, 53:1, 57, 57:1, 112, 122, 123 Examples include 139, 144, 146, 149, 150, 166, 168, 175, 176, 177, 178, 184, 185, 190, 202, 209, 221, 222, 224 and 238; CI Pigment Violet 19 and 196; CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 16, 22 and 60; CI Pigment Green 7 and 36; and solid solutions of these pigments. Water-based inks may be prepared by dispersing pigments in water with a dispersant. As the dispersant, for example, a general polymer dispersant may be used, or it may be prepared in-house. Polymer dispersants include pigment dispersion resins, resin dispersants, etc. In addition, in water-based inks, the pigments may be encapsulated by polymers.

[0013] One method for dispersing pigments using pigment dispersion resins is to disperse the pigments using a dispersion apparatus. The dispersion apparatus used for dispersing pigments is not particularly limited as long as it is a general-purpose disperser, but examples include ball mills, roll mills, and sand mills.

[0014] The pigment may be a self-dispersing pigment. A self-dispersing pigment is one in which, for example, at least one of a hydrophilic functional group such as a carbonyl group, hydroxyl group, carboxylic acid group, sulfonic acid group, or phosphate group, or a salt thereof, is introduced into the pigment particles by chemical bonding, either directly or via other groups, so that it can be dispersed in water without the use of a dispersant.

[0015] Pigments may be used individually or in combination of two or more types. The pigment solid content relative to the total amount of aqueous ink (pigment solid content) is not particularly limited and can be appropriately determined based on the desired optical density or saturation. The range of pigment solid content is, for example, 0.10% to 20.00% by mass, 0.50% to 15.00% by mass, 1.00% to 10.00% by mass, and 2.00% to 8.00% by mass. The pigment solid content is the mass of the pigment only and does not include the mass of resin dispersants, etc. In other words, the pigment solid content is calculated on an effective ingredient basis.

[0016] (binder) The binder is formulated to improve the fixation and friction fastness of the pigment to the fabric by forming a resin coating on the fabric. The binder may be formulated, for example, in the form of an emulsion in an aqueous ink, or dispersed in the aqueous ink in the form of resin particles. The binder contains an acrylic resin.

[0017] Acrylic resins include, as monomers, unsaturated carboxylic acids such as (meth)acrylic acid and (anhydride) maleic acid; (meth)acrylic acid esters having aliphatic hydrocarbon groups, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, oleyl (meth)acrylate, and eicosyl (meth)acrylate; and 2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. The resin is obtained by polymerizing (meth)acrylic acid ester compounds having a hydroxyalkyl group, such as hydroxypropyl and 3-hydroxypropyl (meth)acrylic acid; vinyl monomers such as (meth)acrylamide, acrylonitrile, and olefin compounds; styrene monomers such as styrene, α-methylstyrene, vinyltoluene, dimethylstyrene, ethylstyrene, isopropylstyrene, t-butylstyrene, chlorostyrene, dichlorostyrene, bromostyrene, and fluorostyrene; benzyl (meth)acrylate monomers such as benzyl (meth)acrylate; and phenyl (meth)acrylate monomers such as phenyl (meth)acrylate. In this specification, "(meth)acrylic" means acrylic and / or methacrylic. Also, "(meth)acrylate" means acrylate and / or methacrylate.

[0018] Commercially available acrylic resins may be used. Examples of commercially available products include "Movinyl (registered trademark) 6750", "Movinyl 6760", "Movinyl 6770", "Movinyl 6775", "Movinyl 6960", "Movinyl 6751D", "Movinyl 6899D", "Movinyl 6969D", "RA-071B1", and "RA-071B2" manufactured by Japan Coating Resin Co., Ltd. These binders may be used individually or in combination of two or more types.

[0019] The acrylic resin may be anionic, nonionic, or cationic. Further, the acrylic resin preferably has a property of not generating aggregates when added dropwise to a 0.05 mass% calcium aqueous solution. As described above, when a fabric material is pretreated with a cationic pretreatment liquid, the surface of the fabric material is positively charged. When the acrylic resin has the above property, the acrylic resin disperses without aggregating on the surface of the fabric material that has been positively charged by the pretreatment liquid, and a favorable resin coating film can be formed. As used herein, the term "aggregate" means an agglomerate with an increased size relative to the particles, which is formed by interactions such as chemical bonds and electrostatic forces acting between the particles dispersed in a solvent.

[0020] The content of the binder relative to the total amount of the aqueous ink is not particularly limited. The lower limit of the content in terms of solid content is, for example, 1.00 mass% or more, 2.00 mass% or more, 2.50 mass% or more, 3.00 mass% or more, or 3.50 mass% or more. The upper limit of the content in terms of solid content is, for example, 15.00 mass% or less, 10.00 mass% or less, 9.00 mass% or less, 8.00 mass% or less, or 7.00 mass% or less. The range of the content can be set by appropriately combining the above upper and lower limits. The range of the content in terms of solid content is, for example, from 1.00 mass% to 15.00 mass%, from 2.00 mass% to 10.00 mass%, from 2.50 mass% to 9.00 mass%, from 3.00 mass% to 8.00 mass%, or from 3.50 mass% to 7.00 mass%. When the content of the binder is within the above range, the pigment can be favorably fixed to the fabric material, and high rub fastness of the resin coating film can be ensured.

[0021] The aqueous ink may further contain other water-dispersible resins in addition to the acrylic resin as the binder. Examples of the water-dispersible resin include polycarbonate-based resins, styrene-based resins, polyester-based resins, polyurethane-based resins, and the like.

[0022] (Crosslinking agent) The crosslinking agent is incorporated to impart crosslinkability to the binder. The crosslinking agent comprises at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound.

[0023] As the oxazoline group-containing compound, a compound containing two or more oxazoline groups in the molecule is preferable. The oxazoline group-containing compound can suitably crosslink the binder including the aforementioned acrylic resin, and can form a sufficient resin coating film. Therefore, high washing fastness can be obtained.

[0024] Examples of the oxazoline group-containing compound include 2,2'-bis(2-oxazoline), 2,2'-methylene-bis(2-oxazoline), 2,2'-ethylene-bis(2-oxazoline), 2,2'-trimethylene-bis(2-oxazoline), 2,2'-tetramethylene-bis(2-oxazoline), 2,2'-hexamethylene-bis(2-oxazoline), 2,2'-octamethylene-bis(2-oxazoline), 2,2'-ethylene-bis(4,4'-dimethyl-2-oxazoline), 2,2'-p-phenylene-bis(2-oxazoline), 2,2'-m-phenylene-bis(2-oxazoline), 2,2'-m-phenylene-bis(4,4'-dimethyl-2-oxazoline), bis(2-oxazolinylcyclohexane) sulfide, bis(2-oxazolinylnorbornane) sulfide, oxazoline group-containing polymers, and the like.

[0025] Oxazoline group-containing polymers can be produced by conventionally known manufacturing methods. For example, one or more addition-polymerizable oxazolines, or a monomer component including an addition-polymerizable oxazoline and a monomer copolymerizable thereto, can be used. Preferred copolymerizable monomers are those that do not have a functional group that reacts with the oxazoline group and are copolymerizable with the addition-polymerizable oxazoline. For example, monomers containing ethylenically unsaturated double bonds that do not have a functional group that reacts with the oxazoline group can be used. Examples include vinyl monomers such as vinyl acetate, vinyl chloride, acrylonitrile, acrylamide, and vinyl benzoate; (meth)acrylic monomers such as (meth)acrylic acid esters; styrene monomers such as styrene, α-methylstyrene, and chloromethylstyrene; and olefin monomers such as ethylene and propylene.

[0026] Examples of addition polymerizable oxazolines include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline.

[0027] Examples of water-soluble oxazoline group-containing polymers include polymers with acrylic polymers, acrylic-styrene polymers, etc. as the main chain and oxazoline groups in the side chains.

[0028] Commercially available oxazoline group-containing compounds may be used. Examples of commercially available products include "Epocross (registered trademark) WS-500", "Epocross WS-700", "Epocross K-2010E", "Epocross K-2020E", and "Epocross K-2035E" manufactured by Nippon Shokubai Co., Ltd.

[0029] As the carbodiimide group-containing compound, a compound containing two or more carbodiimide groups in its molecule is preferred. The carbodiimide group-containing compound can suitably crosslink the binder containing the acrylic resin mentioned above, and can form a sufficient resin coating film. As a result, high wash fastness can be obtained.

[0030] Examples of carbodiimide group-containing compounds include carbodiimide, N,N'-dimethylcarbodiimide, N-ethyl,N'-isopropylcarbodiimide, N,N'-diisopropylcarbodiimide, N,N'-dicyclohexylcarbodiimide, N,N'-diphenylcarbodiimide, N,N'-diacetylcarbodiimide, N,N'-bis(2-propene)-carbodiimide, N,N'-dipyrrolidylcarbodiimide, N,N'-diethoxycarbodiimide, bis(trimethylsilyl)carbodiimide, 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide meth-p-toluenesulfonate, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, calcium cyanamide, and carbodiimide group-containing polymers.

[0031] Examples of polymers containing carbodiimide groups include aromatic polycarbodiimides such as poly(4,4'-diphenylmethanecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(diisopropylphenylcarbodiimide), and poly(triisopropylphenylcarbodiimide); alicyclic polycarbodiimides such as poly(dicyclohexylmethanecarbodiimide); and aliphatic polycarbodiimides such as poly(diisopropylcarbodiimide).

[0032] Commercially available compounds containing a carbodiimide group may be used. Examples of commercially available products include "Carbodilite (registered trademark) V-02", "Carbodilite SV-02", "Carbodilite V-04", "Carbodilite V-10", "Carbodilite E-02", and "Carbodilite E-05" manufactured by Nisshinbo Chemical Co., Ltd.

[0033] The crosslinking agents described above may be used individually or in combination of two or more. Among the crosslinking agents described above, it is preferable to include a water-soluble crosslinking agent from the viewpoint of excellent crosslinking performance. Furthermore, it is preferable to include an oxazoline group-containing compound from the viewpoint of improving reactivity with the binder. Among the commercially available products described above, for example, Epocross WS-500, Epocross WS-700, and Carbodilite V-02 are preferred.

[0034] The amount of crosslinking agent is adjusted as appropriate according to the total amount of solids in the binder, crosslinking agent, and wax particles described later. Specifically, the ratio of the amount of crosslinking agent to the total amount should be 0.05 or more in terms of solids, for example, 0.09 or more, 0.14 or more, or 0.17 or more. There is no particular upper limit to the ratio of the amount of crosslinking agent to the total amount. The upper limit of the ratio may be, for example, 1.00 or less, 0.50 or less, 0.30 or less, 0.27 or less, or 0.25 or less in terms of solids. If the ratio of the amount of crosslinking agent to the total amount is 0.05 or more, the binder can be sufficiently crosslinked, a strong resin coating film is formed, and the friction fastness is improved.

[0035] The amount of crosslinking agent relative to the total amount of water-based ink is not particularly limited. The lower limit of the amount is, for example, 0.10% by mass or more, 0.15% by mass or more, 0.20% by mass or more, 0.25% by mass or more, and 0.30% by mass or more, on a solid content basis. The upper limit of the amount is, for example, 10.00% by mass or less, 5.00% by mass or less, 3.00% by mass or less, 2.20% by mass or less, and 2.00% by mass or less, on a solid content basis. The range of the amount can be set by appropriately combining the upper and lower limits mentioned above. The range of the amount is, for example, 0.10% by mass or more and 10.00% by mass or less, 0.15% by mass or more and 5.00% by mass or less, 0.20% by mass or more and 3.00% by mass or less, 0.25% by mass or more and 2.20% by mass or less, and 0.30% by mass or more and 2.00% by mass or less, on a solid content basis.

[0036] Furthermore, in addition to oxazoline group-containing compounds and / or carbodiimide group-containing compounds, the water-based ink may further contain other crosslinking agents. Examples of other crosslinking agents include isocyanate group-containing compounds, aziridine group-containing compounds, epoxy group-containing compounds, and the like.

[0037] (wax particles) Wax particles are added to improve the color development of water-based inks and the friction fastness of resin coatings. Pretreatment of fabric materials with a pretreatment solution is performed, for example, to improve color development. However, even when a pretreatment solution is used, it is difficult to achieve sufficient color development with water-based inks. As mentioned above, when fabric materials are pretreated with a cationic pretreatment solution, the surface of the fabric material becomes positively charged. The wax particles in this embodiment are anionic. Therefore, when water-based ink containing these wax particles is applied to the surface of the pretreated fabric material, the presence of positive charges causes interactions between the wax particles, which can cause them to aggregate. The presence of these aggregated wax particles on the surface of the fabric material inhibits the penetration of pigment in the thickness direction of the fabric material, allowing the pigment to remain on the surface of the fabric material. As a result, it is believed that the color development of water-based inks can be improved. Furthermore, since some of the wax particles present in the resin coating are distributed to cover the surface of the resin coating, it is believed that the friction fastness of the resin coating can be improved. Furthermore, the wax particles may have the property of forming aggregates when dropped into a 0.05% by mass calcium aqueous solution. If they have this property, the aggregates formed when aqueous ink is applied to the surface of a positively charged fabric further suppress the penetration of the pigment in the thickness direction of the fabric, thereby improving color development.

[0038] The wax particles contain wax. Examples of waxes include natural waxes and synthetic waxes. The wax particles may also contain components other than wax. However, from the viewpoint of improving friction fastness, the wax content in the wax particles is preferably, for example, 80.00% by mass or more and 100% by mass or less. It is more preferable that the wax particles consist solely of wax.

[0039] Examples of natural waxes include petroleum-based waxes such as paraffin wax and microcrystalline wax; lignite-based waxes such as montane wax; plant-based waxes such as carnauba wax and candelilla wax; and animal and plant-based waxes such as beeswax and lanolin. Examples of synthetic waxes include polyethylene wax, polypropylene wax, oxidized polyethylene wax, polyalkylene wax, oxidized polyalkylene wax, and silicone wax. Among these, synthetic waxes are preferred, and polyethylene wax, oxidized polyethylene wax, and paraffin wax are particularly preferred. The wax particles may be, for example, a wax emulsion. A wax emulsion is composed of, for example, wax particles and a dispersion medium, in which the wax particles are dispersed in the dispersion medium with a specific particle size, rather than being dissolved.

[0040] You can use commercially available wax. Examples of commercially available products include BYK-Chemie's "CERAFLOUR(registered trademark) 925", "CERAFLOUR929", "CERAFLOUR950", "CERAFLOUR991", "AQUACER(registered trademark) 507", "AQUACER526", "AQUACER537", "AQUACER1547", "AQUAMAT(registered trademark) 208", "AQUAMAT263", "AQUAMAT272", etc.; Mitsui Chemicals, Inc.'s "CHEMIPEARL(registered trademark) W100", "CHEMIPEARL W200", "CHEMIPEARL W300", "CHEMIPEARL W400", "CHEMIPEARL W500", "CHEMIPEARL W700", "CHEMIPEARL W800", "CHEMIPEARL W900"; and Toho Chemical Industry Co., Ltd.'s "HITECH E-7100S", "HITECH E-8237", "HITECH E-6314", "HITECH E-6700", "HITECH E-8010", etc. Among these, for example, oxidized high-density polyethylene wax and paraffin wax are preferred. Specifically, for example, "AQUACER1547" and "AQUACER537" are preferred.

[0041] The melting point of the wax particles is not particularly limited. The melting point of the wax particles should be such that the wax particles melt to a suitable degree when the water-based ink applied to the fabric is heated and dried. Examples of melting points for wax particles include 70°C to 160°C, 90°C to 150°C, and 100°C to 140°C.

[0042] Wax particles may be used individually or in combination of two or more types. The amount of wax particles can be adjusted as appropriate according to the amount of binder described above. The ratio of wax particles to binder is not particularly limited. The lower limit of this ratio, in terms of solid content, is, for example, 0.05 or more, 0.07 or more, 0.09 or more, 0.14 or more, and 0.20 or more. The upper limit of this ratio, in terms of solid content, is, for example, 1.00 or less, 0.80 or less, 0.70 or less, 0.60 or less, and 0.50 or less. The range of this ratio can be set by appropriately combining the upper and lower limits described above. The range of this ratio is, for example, 0.05 to 1.00, 0.07 to 0.80, 0.09 to 0.70, 0.14 to 0.60, and 0.20 to 0.50. If the ratio is within the above range, the aggregated wax particles remain on the surface of the fabric, allowing the pigment to stay on the fabric surface. This improves the color development of the water-based ink. Furthermore, because the wax particles and binder are blended in an appropriate ratio, high wash fastness and high abrasion fastness can be achieved.

[0043] The amount of wax particles relative to the total amount of water-based ink is not particularly limited. The lower limit of the amount is, for example, 0.10% by mass or more, 0.20% by mass or more, 0.50% by mass or more, 0.75% by mass or more, and 1.00% by mass or more, on a solid content basis. The upper limit of the amount is, for example, 5.00% by mass or less, 4.00% by mass or less, 3.00% by mass or less, 2.50% by mass or less, and 2.00% by mass or less, on a solid content basis. The range of the amount can be set by appropriately combining the upper and lower limits mentioned above. The range of the amount is, for example, 0.10% by mass or more and 5.00% by mass or less, 0.20% by mass or more and 4.00% by mass or less, 0.50% by mass or more and 3.00% by mass or less, 0.75% by mass or more and 2.50% by mass or less, and 1.00% by mass or more and 2.00% by mass or less, on a solid content basis. If the wax particle content is within the above range, the wax particles will be distributed to cover the surface of the resin coating. As a result, good abrasion resistance can be imparted to the resin coating, improving its friction fastness.

[0044] (Other ingredients) Water-based inks may further contain water, water-soluble organic solvents, and surfactants as other components.

[0045] (water) The water is preferably deionized water or pure water. The water content relative to the total amount of water-based ink is appropriately determined according to the desired ink characteristics, etc. The range of water content is, for example, 15.00% by mass or more and 95.00% by mass or less, 35.00% by mass or more and 85.00% by mass or less, or 50.00% by mass or more and 80.00% by mass or less. The water content may, for example, be the remainder of the other components.

[0046] (Water-soluble organic solvent) Examples of water-soluble organic solvents include wetting agents and penetrating agents.

[0047] The wetting agents are not particularly limited and include, for example, lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones such as acetone; keto alcohols such as diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyethers such as polyalkylene glycol; polyhydric alcohols such as alkylene glycol, glycerin, trimethylolpropane, and trimethylolethane; 2-pyrrolidone; N-methyl-2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone; and the like. Examples of polyalkylene glycols include polyethylene glycol and polypropylene glycol. Examples of alkylene glycols include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, thiodiglycol, and hexylene glycol. These wetting agents may be used individually or in combination of two or more types. Among these, glycerin, polyethylene glycol, and the like are preferred.

[0048] A single type of wetting agent may be used alone, or two or more types may be used in combination. When a water-based ink contains a wetting agent, the amount of wetting agent relative to the total amount of water-based ink is not particularly limited. The range of the wetting agent is, for example, 1.00% by mass or more and 95.00% by mass or less, 5.00% by mass or more and 80.00% by mass or less, or 10.00% by mass or more and 50.00% by mass or less. When a water-based ink contains a wetting agent, if the wetting agent content is within the above range, drying of the ink during storage can be prevented, and the storage stability of the ink can be improved.

[0049] Examples of penetrating agents include glycol ethers. Examples of glycol ethers include ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol-n-propyl ether, diethylene glycol-n-butyl ether, diethylene glycol-n-hexyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol-n-propyl ether, triethylene glycol-n-butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol-n-propyl ether, propylene glycol-n-butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol ethyl ether, tripropylene glycol-n-propyl ether, and tripropylene glycol-n-butyl ether. Among these, triethylene glycol-n-butyl ether is preferred.

[0050] Penetrants may be used individually or in combination of two or more types. When an aqueous ink contains a penetrant, the amount of penetrant relative to the total amount of aqueous ink is not particularly limited. The range of the content is, for example, 0.10% by mass or more and 20.00% by mass or less, 0.50% by mass or more and 10.00% by mass or less, and 1.00% by mass or more and 5.00% by mass or less.

[0051] (Surfactants) The surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples of surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, silicone-based surfactants, and fluorine-based surfactants.

[0052] Examples of anionic surfactants include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, N-acyl amino acids or their salts, N-acyl methyl taurates, alkyl sulfates, polyoxyalkyl ether sulfates, alkyl sulfates, polyoxyethylene alkyl ether phosphates, rosinic acid soaps, castor oil sulfates, lauryl alcohol sulfates, alkylphenol type phosphates, alkyl type phosphates, alkylaryl sulfonates, diethyl sulfosaturates, diethylhexyl sulfosaturates, and dioctyl sulfosaturates.

[0053] Examples of nonionic surfactants include polyols, glycol ethers, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene alkylamides, and acetylene glycols. Commercially available nonionic surfactants may also be used. Examples of commercially available products include "Orphin® E1004," "Orphin E1008," and "Orphin E1010" from Nisshin Chemical Industry Co., Ltd.; "Surfinol® 440," "Surfinol 465," and "Surfinol 485" from Air Products and Chemicals; and "Acetylenel® E40" and "Acetylenel E100" from Kawaken Fine Chemical Co., Ltd.

[0054] Examples of silicone-based surfactants include polyether-modified siloxanes and polyether-modified polydimethylsiloxanes. Commercially available silicone-based surfactants may also be used. Examples of commercially available products include "Dynol 960" and "Dynol 980" from Air Products and Chemicals; "Sylface (registered trademark) SAG002," "Sylface SAG005," and "Sylface SAG503A" from Nisshin Chemical Industry Co., Ltd.; "BYK (registered trademark)-345," "BYK-347," "BYK-348," "BYK-349," "BYK-3420," "BYK-3455," "BYK-3456," "LP-X23288," "LP-X23289," and "LP-X23347" from BYK-Chemie; and "TEGO (registered trademark) Twin4000" and "TEGO Wet KL245" from Evonik Tego Chemie.

[0055] Examples of fluorine-based surfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in their side chains.

[0056] Surfactants may be used individually or in combination of two or more types. When an aqueous ink contains a surfactant, the amount of surfactant relative to the total amount of aqueous ink is not particularly limited. The range of the amount is, for example, 0.10% by mass or more and 20.00% by mass or less, 0.15% by mass or more and 10.00% by mass or less, and 0.20% by mass or more and 5.00% by mass or less. When an aqueous ink contains a surfactant, if the amount of surfactant is within the above range, it can impart a suitable surfactant effect to the aqueous ink.

[0057] Water-based inks may also contain conventionally known additives as needed. Examples of additives include pH adjusters, viscosity modifiers, and preservatives. Examples of viscosity modifiers include polyvinyl alcohol, cellulose, and water-soluble resins.

[0058] Water-based inks can be prepared, for example, by uniformly mixing a pigment, a binder, a crosslinking agent, wax particles, water, and other components as needed, using conventionally known methods, and then removing insoluble materials using a filter or the like.

[0059] As mentioned above, water-based inks contain solids derived from various components. The storage stability of water-based inks can be improved by appropriately setting the total amount of solids from the binder, crosslinking agent, and wax particles relative to the total amount of ink. The total amount of solids from the binder, crosslinking agent, and wax particles relative to the total amount of ink is not particularly limited. The lower limit of the total amount of solids from the binder, crosslinking agent, and wax particles relative to the total amount of ink is, for example, 5.00% by mass or more, 5.50% by mass or more, 6.00% by mass or more, 6.30% by mass or more, and 6.60% by mass or more. The upper limit of the total amount of solids from the binder, crosslinking agent, and wax particles relative to the total amount of ink is, for example, 15.00% by mass or less, 10.00% by mass or less, 9.00% by mass or less, 8.20% by mass or less, and 8.00% by mass or less.

[0060] (Ink set) Next, the ink set disclosed herein will be described. The ink set comprises the above-mentioned water-based ink for inkjet recording and a pretreatment solution.

[0061] (Pretreatment solution) The pretreatment solution is applied to the fabric before forming an image on it using water-based inkjet recording ink. The pretreatment solution, for example, prevents the pigments contained in the water-based ink from seeping into the fabric. The pretreatment solution is cationic and contains a coagulant.

[0062] (Flocculant) Coagulants are added to water-based inks to facilitate the aggregation of components, thereby suppressing ink bleeding and improving pigment fixation and color development. Examples of coagulants include organic acids, cationic compounds, and polyvalent metal salts.

[0063] Examples of organic acids include monocarboxylic acids and their salts such as formic acid, acetic acid, propionic acid, butyric acid, benzoic acid, glycolic acid, lactic acid, salicylic acid, pyrrole carboxylic acid, furoic acid, picolinic acid, nicotinic acid, thiophene carboxylic acid, levulinic acid, and coumaric acid; dicarboxylic acids and their salts or hydrogen salts such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, itaconic acid, sebacic acid, phthalic acid, malic acid, and tartaric acid; tricarboxylic acids and their salts or hydrogen salts such as citric acid and trimellitic acid; and tetracarboxylic acids and their salts or hydrogen salts such as pyromellitic acid.

[0064] Examples of cationic compounds include cationic resins and cationic surfactants.

[0065] Examples of cationic resins include resins having primary, secondary, and tertiary amine structures, and resins having quaternary ammonium salt structures. Specifically, examples include resins having structures such as vinylamine, allylamine, vinylimidazole, vinylpyridine, dimethylaminoethyl methacrylate, ethyleneimine, guanidine, diallyldimethylammonium chloride, and alkylamine-epichlorohydrin condensates.

[0066] Examples of cationic surfactants include quaternary ammonium salts, quaternary ammonium ions, primary, secondary, and tertiary amine salt compounds, alkylamine salts, dialkylamine salts, aliphatic amine salts, alkylpyridinium salts, imidazolinium salts, sulfonium salts, phosphonium salts, and onium salts. Specific examples of cationic surfactants other than quaternary ammonium salts and quaternary ammonium ions include hydrochloride and acetate salts of laurylamine, coconutamine, rosinamine, etc., as well as cetylpyridinium chloride, cetylpyridinium bromide, and dihydroxyethyl laurylamine.

[0067] Examples of polyvalent metal salts include aluminum chloride, aluminum bromide, aluminum sulfate, aluminum nitrate, aluminum acetate, barium chloride, barium bromide, barium iodide, barium oxide, barium nitrate, barium thiocyanate, calcium chloride, calcium bromide, calcium iodide, calcium nitrite, calcium nitrate, calcium dihydrogen phosphate, calcium thiocyanate, calcium lactate, calcium fumarate, calcium citrate, copper chloride, copper bromide, copper sulfate, copper nitrate, copper acetate, and chloride. Examples include iron, iron bromide, iron iodide, iron sulfate, iron nitrate, iron oxalate, iron lactate, iron fumarate, iron citrate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate, manganese sulfate, manganese nitrate, manganese dihydrogen phosphate, manganese acetate, manganese salicylate, manganese benzoate, manganese lactate, nickel chloride, nickel bromide, nickel sulfate, nickel nitrate, nickel acetate, tin sulfate, titanium chloride, zinc chloride, zinc bromide, zinc sulfate, zinc nitrate, zinc thiocyanate, zinc acetate, etc.

[0068] The coagulant may be one type from the above list used alone, or two or more types may be used in combination. The content of the coagulant relative to the total amount of the pretreatment liquid is not particularly limited. The range of the content is, for example, 0.50% by mass or more and 20.00% by mass or less, 1.00% by mass or more and 20.00% by mass or less, and 1.00% by mass or more and 15.00% by mass or less.

[0069] The pretreatment solution may further contain additives such as solvents, pH adjusters, and preservatives, as needed.

[0070] (Inkjet recording device) Next, the inkjet recording device 10 of the embodiment will be described with reference to the drawings. Hereinafter, the inkjet recording device 10 may be simply referred to as the recording device 10. The recording device 10 is a device that ejects water-based inkjet recording ink toward a fabric material according to an inkjet recording method and records an image toward the fabric material. In this embodiment, the recording device 10 is a device that performs printing on a fabric material by an inkjet recording method. The recording device 10 is used by being placed on a table. However, in other embodiments, the recording device 10 may be used by being placed on the floor or on a rack.

[0071] As shown in Figure 1, the recording device 10 comprises a storage tank 11, a carriage 12, a discharge head 13, a pair of transport rollers 14, a pair of guide rails 15, a sub-tank 16, and a control unit 20. The control unit 20 is communicatively connected to each part of the recording device 10 and controls the operation of each part. The control unit 20 is also communicatively connected to a pre-treatment liquid coating device 22, which will be described later, and controls the operation of the pre-treatment liquid coating device 22. The fabric material 30, which is the object of image formation, is placed on the platen of the recording device 10.

[0072] A discharge head 13 is mounted on the carriage 12. The carriage 12 is supported by a pair of guide rails 15. The carriage 12 reciprocates along the guide rails 15 in the direction of movement Ds. As a result, the discharge head 13 reciprocates in the direction of movement Ds. The direction of movement Ds is perpendicular to the direction Df of fabric material transport.

[0073] The carriage 12 is equipped with multiple sub-tanks 16. Each sub-tank 16 is connected to a corresponding storage tank 11 via a tube for circulating ink. In Figure 1, the sub-tanks 16 are schematically shown as a single structure.

[0074] A pair of conveyor rollers 14 are arranged parallel to each other along the direction of movement Ds. The conveyor rollers 14 rotate when driven by a conveyor motor, thereby conveying the fabric material 30 on the platen in the conveying direction Df.

[0075] Water-based ink is stored in the storage tank 11. The storage tank 11 is connected to the discharge head 13 via a tube and a sub-tank 16. A separate storage tank 11 is provided for each type of water-based ink. In Figure 1, the storage tank 11 is schematically shown as a single structure, but the recording device 10 may have, for example, five storage tanks 11. The five storage tanks 11 each store water-based ink of white, black, yellow, cyan, and magenta.

[0076] As shown in Figure 2, the carriage 12 is equipped with two discharge heads 13A and 13B. Discharge heads 13A and 13B are aligned along the transport direction Df. When recording an image on the fabric material 30, the carriage 12 is moved along the movement direction Ds. As a result, the discharge heads 13A and 13B move together with the carriage 12. At this time, the discharge heads 13 discharge water-based ink onto the fabric material 30, thereby recording an image on the recording surface of the fabric material 30. In the image recording process, the process of transporting the fabric material 30 in the transport direction Df and the process of moving the discharge heads 13 while discharging water-based ink are repeated alternately.

[0077] The ejection head 13A ejects white ink. The ejection head 13A is provided with a row of nozzles NL for ejecting white ink, arranged along the transport direction Df. In the example shown in Figure 2, the ejection head 13A has four rows of nozzles NL for ejecting white ink, arranged at regular intervals along the movement direction Ds. The number of nozzle rows NL for ejecting white ink is not particularly limited. For example, there may be two rows or one row of nozzles NL for ejecting white ink.

[0078] The ejection head 13B ejects water-based inks of yellow, magenta, cyan, and black. The ejection head 13B is provided with nozzle rows NL for ejecting each water-based ink, along the transport direction Df. Each nozzle row NL is arranged at a constant interval along the movement direction Ds.

[0079] In addition to the five storage tanks 11 for storing each of the aforementioned water-based inks, the recording device 10 may also include a storage tank for storing special color inks. In this case, for example, one of the nozzle rows NL of the discharge head 13A may be used to discharge the special color ink.

[0080] (Image forming method) Next, an image formation method using an inkjet recording method with a recording device 10 will be described. This image formation method comprises a pre-treatment step, a pre-treatment liquid fixing step, an image formation step, and a drying step. The control unit 20 executes each step in response to, for example, a command to form an image being input to the recording device 10 from an external source. When the command is input, the control unit 20 transports the fabric material 30 by controlling various parts such as a pair of transport rollers 14.

[0081] (Pre-treatment process) In the pretreatment step, the control unit 20 applies a pretreatment solution to the recording surface of the cloth material 30. The pretreatment step is performed with the aim of suppressing the bleeding of water-based ink and improving the fixation and color development of pigments. The specific configuration for applying the pretreatment solution to the cloth material 30 is not particularly limited. For example, as shown in Figure 3, the pretreatment solution can be applied to the cloth material 30 using a pretreatment solution application device 22 that is independent of the recording device 10. The control unit 20 controls the operation of the pretreatment solution application device 22 to apply the pretreatment solution to the recording surface of the cloth material 30 as it passes through the pretreatment solution application device 22.

[0082] The method of applying the pretreatment solution to the fabric material 30 is not particularly limited. Examples of pretreatment solution application methods include spray coating, blade coating, roll coating, inkjet, and immersion processing methods. The immersion processing method involves immersing the fabric material 30 in the pretreatment solution and then squeezing the fabric material 30 with a mangle roll. From the viewpoint of continuously performing the application of the pretreatment solution and image formation with water-based ink, an inkjet method may be adopted.

[0083] In the pretreatment step, the pretreatment solution is applied to the image-forming area with water-based ink. The pretreatment solution may be applied to the entire recording surface of the cloth material 30, or to only a portion of the area including the image-forming area. In the former case, a spray coating method, blade coating method, roll coating method, immersion processing method, etc., can be suitably employed. In the latter case, an inkjet method can be suitably employed.

[0084] Furthermore, the recording device 10 itself may also have the function of a pretreatment liquid coating device 22. That is, the recording device 10 may be configured to coat the fabric material 30 with pretreatment liquid. Also, if the pretreatment liquid is coated by an inkjet method, a separate discharge head for coating the pretreatment liquid may be provided on the carriage 12 of the recording device 10.

[0085] (Pretreatment solution fixing process) In the pretreatment solution fixing process, the control unit 20 fixes the pretreatment solution applied to the cloth material 30 to the recording surface of the cloth material 30 by drying it. The control unit 20 fixes the pretreatment solution to the recording surface of the cloth material 30 by controlling the drying device provided in the pretreatment solution application device 22.

[0086] The method for drying the pretreatment solution is not particularly limited. Examples of pretreatment solution drying methods include air drying and heating with equipment. Examples of equipment include commercially available irons, heat presses, dryers, ovens, and belt conveyor ovens.

[0087] (image forming process) In the image forming process, the control unit 20 ejects water-based ink onto the recording surface of the transported fabric material 30. The control unit 20 controls piezoelectric elements, etc., corresponding to each nozzle provided on the carriage 12 and the ejection head 13, to selectively eject water-based ink from each nozzle toward the fabric material 30 passing below the ejection head 13. As a result, a predetermined image is formed on the recording surface of the fabric material 30.

[0088] (drying process) In the drying process, the control unit 20 heats the cloth material 30 coated with the aqueous ink to dry the aqueous ink. The control unit 20 controls, for example, a drying device provided in the recording device 10 to dry the aqueous ink adhering to the recording surface of the cloth material 30. As a method for drying the aqueous ink, various drying methods described above in the pretreatment solution fixing process can be employed. In the drying process, heating the cloth material 30 melts the wax particles. Since a cationic pretreatment solution is fixed to the surface of the cloth material 30, the surface of the cloth material 30 is positively charged. Therefore, due to the presence of positive charges, interactions occur between the melted wax particles, causing the wax particles to aggregate. The aggregated wax particles have difficulty penetrating in the thickness direction of the cloth material 30 and remain on the surface of the cloth material 30. The presence of these wax particles suppresses the penetration of pigment in the thickness direction of the cloth material 30, allowing the pigment to remain suitably on the surface of the cloth material 30. Furthermore, during the drying process, heating the fabric material 30 promotes a cross-linking reaction between the binders by the cross-linking agent, forming a strong resin coating. In this way, the drying process involves heating and drying the fabric material 30 on which the image has been recorded, thereby effectively fixing the pigment to the fibers constituting the fabric material 30. By performing the above steps, a desired image can be formed on the fabric material 30.

[0089] The heating temperature of the fabric material 30 in the drying process is not particularly limited. For example, the heating temperature can be 80°C to 200°C, 100°C to 190°C, 110°C to 185°C, or 130°C to 180°C. It is preferable to set the heating temperature considering the melting point of the wax particles. In the drying process, the wax particles melt and some of the wax particles are distributed to cover the surface of the resin coating, thereby improving the lubricity of the coating surface. This is thought to improve the dry friction fastness. Therefore, from the viewpoint of melting the wax particles, the heating temperature should be above the melting point of the wax particles. However, in this case, the dry friction fastness can be further improved by melting the wax particles so that at least a part of their shape remains, rather than completely melting them. This is thought to be because, when the coating surface is rubbed, the wax particles are scraped off before other components because the particle shape of the wax particles remains on the coating surface to some extent. This suppresses the direct application of frictional force to the binder. Therefore, the heating temperature can be, for example, above the melting point of the wax particles and below (melting point of wax particles + 50°C). The time for drying the same position of the fabric material 30 is not particularly limited, but can be, for example, 120 seconds or more and 600 seconds or less.

[0090] In the above-described embodiment, the control unit 20 of the recording device 10 controlled the operation of the pretreatment liquid coating device 22. However, a separate dedicated control unit for controlling the pretreatment liquid coating device 22 may be provided. Furthermore, the pretreatment liquid fixing step does not have to be performed. In other words, the image forming method disclosed herein only needs to include at least a pretreatment step, an image forming step, and a drying step. [Examples]

[0091] Next, the aqueous inks disclosed herein will be described in detail with reference to examples and comparative examples. However, the technologies disclosed herein are not limited in any way to these examples.

[0092] (Preparation of the aqueous ink in Example 1) A total of 89.55% by mass of a water-soluble organic solvent and water was prepared. To this water-soluble organic solvent and water, 4.50% by mass of Movinyl 6770 as a binder (based on solid content), 1.20% by mass of Epocross WS-700 as a crosslinking agent (based on solid content), 1.50% by mass of AQUACER 1547 as wax particles (based on solid content), and 0.25% by mass of BYK-3420 as a surfactant were added and mixed. Finally, 3.00% by mass of black pigment dispersion (based on solid content) was added and mixed as a pigment. The resulting mixture was filtered through a cellulose acetate type membrane filter (pore size 3.00 μm) manufactured by Toyo Roshi Co., Ltd. to obtain the aqueous ink of Example 1.

[0093] (Preparation of aqueous inks for Examples 2-18 and Comparative Examples 1-4) Except for the types and amounts of components listed in Tables 1 and 2, the same procedure as in the preparation of the aqueous ink in Example 1 was followed to obtain the aqueous inks for each example.

[0094] [Table 1]

[0095] [Table 2]

[0096] In Tables 1 and 2, the black pigment dispersion is an aqueous dispersion of carbon black, and the magenta pigment dispersion is an aqueous dispersion of CI Pigment Red 122. Furthermore, the content of each component in each example represents the solid content or active ingredient content of that component relative to the total amount of aqueous ink.

[0097] (Preparation of evaluation samples) As a pretreatment step, a 350mm x 350mm piece of 100% cotton white woven fabric was coated with 80.00 g / m2 of a calcium nitrate aqueous solution diluted to 0.30% by mass as a pretreatment solution, and dried in an oven set to 120°C for 3 minutes to obtain a pretreated woven fabric. The pretreated woven fabric was set in a Brother Industries, Ltd. GTX® pro garment printer. Using the water-based inks prepared for each example, the amount ejected from the inkjet head was adjusted to 20 pL per pixel, and an image was formed on the pretreated woven fabric by solid printing at a resolution of 1200 dpi x 1200 dpi. After image formation, the pretreated woven fabric was heated in an oven set to 160°C for 5 minutes to obtain an evaluation sample.

[0098] For each example and comparative example, the storage stability of the ink, the color development of the ink, the dry rubbing fastness, the wet rubbing fastness, and the washing fastness were evaluated according to the methods described below.

[0099] (Evaluation of ink storage stability) Each prepared aqueous ink sample was placed in a sealed container and stored for one week in a constant temperature bath manufactured by ESPEC Corporation and set to 60°C. The viscosity before and after one week of storage was measured at 25°C using a TVE-25 viscometer manufactured by Toki Sangyo Co., Ltd. The percentage change in viscosity after storage compared to before storage was calculated, and the storage stability of the aqueous ink was evaluated according to the following criteria. The evaluation results are shown in Tables 1 and 2. A: Rate of change is less than 10% B: Change rate of 10% or more

[0100] (Evaluation of ink color development) For each evaluation sample, the optical density (OD value) of five randomly selected locations within the image-formed area was measured using an X-Rite eXact spectrophotometer under the following conditions. Light source: D65, Field of view: 10°, Measurement mode: ANSI-T The average value of each value was then calculated, and the color development of the water-based ink was evaluated based on this average value according to the following criteria. The evaluation results and the calculated OD values ​​are shown in Tables 1 and 2. A: OD value is 1.40 or higher B: OD value is 1.35 or higher and less than 1.40 C:OD value is less than 1.35

[0101] (Evaluation of dry friction fastness) For each example, the dry rub fastness grade was calculated for the evaluation sample using a test method compliant with ISO 105-X12, and the dry rub fastness of the water-based ink was evaluated according to the following criteria. The evaluation results and dry rub fastness grades are shown in Tables 1 and 2. AA: Level 3 or above A: 2-3 grade B: 2nd grade C: Level 1-2 or lower

[0102] (Evaluation of wet friction fastness) For each example, the wet rub fastness grade was calculated for the evaluation sample using a test method compliant with ISO 105-X12, and the wet rub fastness of the water-based ink was evaluated according to the following criteria. The evaluation results and wet rub fastness grades are shown in Tables 1 and 2. A: 2-3 grade or higher B: 2nd grade C: Level 1-2 or lower

[0103] (Evaluation of wash fastness) Each evaluation sample was placed in a Toshiba AW-304 household washing machine along with the load fabric. With 45L of water, 30g of a weakly alkaline synthetic laundry detergent for general household use was added, and the wash cycle was run on the standard setting. This procedure was repeated five times. The evaluation samples after five washes were compared to the evaluation samples before washing, and the degree of color fading was determined using the grayscale for color change specified in JIS L0804. Based on the determination results, the wash fastness grade was calculated, and the wash fastness of the water-based ink was evaluated according to the following criteria. The evaluation results and wash fastness grades are shown in Tables 1 and 2. A: Level 3-4 or higher B: 3rd grade C: Level 2-3 or below

[0104] As shown in Tables 1 and 2, good results were obtained for all evaluation items in Examples 1 to 18.

[0105] In contrast, Comparative Example 1 showed lower evaluations of color development and dry rub fastness compared to Example 1. The aqueous ink of Comparative Example 1 has the same composition as the aqueous ink of Example 1, except that it does not contain wax particles. Here, the wax particles "AQUACER1547" contained in the aqueous ink of Example 1 are anionic. The evaluation sample was coated with an aqueous calcium nitrate solution diluted to a calcium concentration of 0.30% by mass. That is, the surface of the evaluation sample is positively charged. Therefore, when the aqueous ink of Example 1 is applied to the evaluation sample, the wax particles aggregate. This suppresses the penetration of the pigment in the thickness direction of the woven fabric, making it easier for the pigment to remain on the surface of the woven fabric, thus improving the color development of the aqueous ink. In contrast, the aqueous ink of Comparative Example 1 does not contain wax particles. Therefore, when the aqueous ink of Comparative Example 1 is applied to the evaluation sample, no aggregates are formed, and the pigment penetrates easily in the thickness direction of the woven fabric. As a result, the pigment did not remain near the surface of the woven fabric, which is thought to have resulted in poor color development of the water-based ink. In addition, wax particles were not present on the surface of the resin coating of the water-based ink in Comparative Example 1, making it impossible to impart good abrasion resistance to the resin coating. Therefore, it is thought that the evaluation of dry abrasion fastness was low.

[0106] Furthermore, Comparative Example 1 received a lower wash fastness rating compared to Example 1. Because the wax particles are distributed so that some of them cover the surface of the resin coating, when the evaluation sample is rubbed, the wax particles are removed before other components, protecting the resin coating. In other words, the wax particles are thought to contribute to the durability of the resin coating. For this reason, in Comparative Example 1, which does not contain wax particles, the resin coating is more likely to peel off during washing, resulting in a lower wash fastness rating.

[0107] Furthermore, Comparative Example 2 showed lower dry rub fastness, wet rub fastness, and wash fastness ratings compared to Example 1. The aqueous ink of Comparative Example 2 has the same composition as the aqueous ink of Example 1, except that it does not contain a crosslinking agent. In Comparative Example 2, because a crosslinking agent is not contained, a crosslinked structure is not formed between the binders, and a resin coating with sufficient strength cannot be obtained. This is thought to be the reason why the dry rub fastness and wet rub fastness ratings were low. In addition, if a crosslinked structure is not formed between the binders, a resin coating that sufficiently covers the pigment cannot be obtained. This is thought to be the reason why the fixation of the pigment is impaired, resulting in a low wash fastness rating.

[0108] Furthermore, Comparative Examples 3 and 4 showed low color development. The aqueous inks of Comparative Examples 3 and 4 have the same composition as the aqueous ink of Example 9, except that they contain different wax particles. The aqueous inks of Comparative Examples 3 and 4 contain wax particles, and since the surface of the resin coating film is covered with wax particles, friction fastness equivalent to that of Example 9 is obtained. However, the wax particles "AQUACER515" and "AQUACER539" contained in the aqueous inks of Comparative Examples 3 and 4 are both nonionic. Therefore, even when the aqueous inks of Comparative Examples 3 and 4 are applied to the evaluation sample, the wax particles do not easily aggregate, and the pigment easily penetrates in the thickness direction of the woven fabric. As a result, the pigment does not easily remain near the surface of the woven fabric, which is thought to be the reason for the low color development of the ink.

[0109] Next, we will compare and examine each example. First, the aqueous inks of Examples 1 to 4 have a common composition, except that they contain different crosslinking agents. The crosslinking agent contained in the aqueous inks of Examples 1 and 2 is an oxazoline group-containing compound. The crosslinking agent contained in the aqueous inks of Examples 3 and 4 is a carbodiimide group-containing compound. As shown in Examples 1 to 4, aqueous inks containing oxazoline group-containing compounds exhibit better dry friction fastness compared to aqueous inks containing carbodiimide group-containing compounds. This is thought to be because oxazoline group-containing compounds have high stability in water-soluble liquids and can form a more suitable crosslinked structure between binders when forming a resin coating film.

[0110] Furthermore, comparing Example 1 and Example 2, Example 1 shows higher dry rub fastness and wash fastness ratings than Example 2. This is thought to be due to the fact that the crosslinking agent "Epocros WS-700" contained in the aqueous ink of Example 1 is water-soluble, while the crosslinking agent "Epocros K-2010E" contained in the aqueous ink of Example 2 is an emulsion. Aqueous inks containing water-soluble crosslinking agents can suitably form crosslinked structures between binders compared to aqueous inks containing emulsion-type crosslinking agents. By forming a sufficient crosslinked structure, the binders become more molecular weight and their hydrophobicity improves. As a result, it is thought that Example 1 showed improved dry rub fastness and wash fastness compared to Example 2.

[0111] The aqueous inks of Examples 5 and 6 have the same composition as the aqueous ink of Example 1, except that the crosslinking agent content differs. In other words, in Examples 1, 5, and 6, the ratio of the crosslinking agent content to the total amount of solids of the binder, crosslinking agent, and wax particles differs from one another. As shown in Examples 1, 5, and 6, the storage stability of the aqueous ink may decrease as this ratio increases. This is thought to be because when the total amount of solids of the binder, crosslinking agent, and wax particles is relatively large, the interaction between resin particles increases, thus reducing storage stability. In addition, the crosslinking reaction may proceed slightly even during storage of the aqueous ink. Therefore, the higher the crosslinking agent content, the more crosslinking points there are, and the easier the crosslinking reaction proceeds. This can increase the viscosity of the aqueous ink. Thus, it is thought that aqueous inks with appropriately set total amounts of solids of the binder, crosslinking agent, and wax particles, and the crosslinking agent content, will have better storage stability.

[0112] The aqueous ink of Example 7 has the same composition as the aqueous ink of Example 1, except that it contains different wax particles. More specifically, the wax particles contained in the aqueous ink of Example 1 are "AQUACER1547," which is oxidized high-density polyethylene wax. On the other hand, the wax particles contained in the aqueous ink of Example 7 are "AQUACER537," which is modified paraffin. Both "AQUACER537" and "AQUACER1547" are anionic. There was almost no difference in the evaluation results between Examples 1 and 7, indicating that aqueous inks containing anionic wax particles yield good results.

[0113] The aqueous inks of Examples 8 and 9 have the same composition as the aqueous ink of Example 1, except that the crosslinking agent content differs. In other words, Examples 1, 8, and 9 differ in the ratio of the crosslinking agent content to the total amount of solids of the binder, crosslinking agent, and wax particles. As shown in Examples 1, 8, and 9, the dry friction fastness may decrease as this ratio decreases. However, even the aqueous ink of Example 9, which has a relatively low crosslinking agent content, can obtain sufficient dry friction fastness. Nevertheless, it is found that aqueous inks containing a certain amount of crosslinking agent form a sufficient crosslinked structure and obtain better dry friction fastness.

[0114] The aqueous ink of Example 10 has the same composition as the aqueous ink of Example 2, except that the crosslinking agent content is different. Although the crosslinking agent content of the aqueous ink of Example 10 is less than that of the aqueous ink of Example 2, there is no difference in the evaluation results between Example 2 and Example 10. From these results, it can be seen that aqueous inks containing a certain amount of crosslinking agent yield good results in each evaluation item.

[0115] The aqueous inks of Examples 11-15 have the same composition as the aqueous ink of Example 1, except that the ratio of wax particle content to binder content differs. More specifically, in Examples 1, 11-15, the total amount of solids of binder, crosslinking agent, and wax particles is the same, but the ratio of wax particle content to binder content differs. As shown in Examples 11-15, the evaluation of the color development of the aqueous ink may decrease as the ratio of wax particle content to binder content decreases. The smaller the above ratio, the lower the relative content of wax particles. In Example 14, where the above ratio is small, the wax particles do not easily aggregate near the surface of the woven fabric, and the effect of suppressing the penetration of pigment in the thickness direction of the woven fabric is difficult to obtain. For this reason, it can be seen that aqueous inks containing a certain amount of wax particles obtain better color development.

[0116] Furthermore, as shown in Examples 11-15, a tendency was observed for the evaluation of dry friction fastness to decrease as the above ratio decreased. Generally, the presence of wax particles on the coating surface improves the lubricity of the coating surface. Therefore, the smaller the above ratio, the less likely it is that the effect of improving the lubricity of the coating surface by wax particles will be obtained. Thus, it can be seen that water-based inks containing a certain amount of wax particles can obtain better dry friction fastness.

[0117] Furthermore, as shown in Examples 11-15, a tendency was observed for the evaluation of wash fastness to decrease as the above ratio increased. It is thought that the larger the above ratio, the lower the relative content of the binder, and the less sufficient resin coating film to fix the pigment to the woven fabric was formed. From this result, it is thought that water-based inks containing a certain amount of binder will obtain better wash fastness. On the other hand, a tendency was observed for wash fastness to decrease as the above ratio decreased. This is thought to be because the smaller the above ratio, the fewer wax particles covering the surface of the resin coating film, making it difficult to obtain the effect of improving the durability of the resin coating film. From this result, it can be seen that water-based inks containing a certain amount of wax particles with an appropriate ratio of wax particle content to binder content will obtain better wash fastness.

[0118] The aqueous inks of Examples 16 and 17 have the same composition as the aqueous ink of Example 1, except that they contain different binders. The binder contained in the aqueous ink of Example 16 is "Movinyl 6760," an acrylic resin. The binder contained in the aqueous ink of Example 17 is "Movinyl 6751D," an acrylic resin. There was almost no difference in the evaluation results between Examples 1, 16, and 17, indicating that aqueous inks containing acrylic resins as binders yield good results.

[0119] The aqueous ink of Example 18 has a common composition with the aqueous ink of Example 1, in that it contains a different pigment. From the evaluation results of Example 18, it can be seen that, regardless of the type of pigment, an aqueous ink in which the type of crosslinking agent and binder, and the ratio of the crosslinking agent content to the total amount of solids of the binder, crosslinking agent, and wax particles are appropriately set yields good results.

[0120] From the above results, it can be seen that an aqueous ink containing an acrylic resin binder, a crosslinking agent containing at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound, and anionic wax particles exhibits suitable color development, high wash fastness, and abrasion fastness by appropriately setting the content of the crosslinking agent relative to the total amount of solids of the binder, crosslinking agent, and wax particles.

[0121] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above.

[0122] Furthermore, the technical elements described herein or in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated herein or in the drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness.

[0123] Even if, in the claims of this patent application, each claim depends on only some of the claims, it is not limited to the claim being dependent only on those specific claims. To the extent that it is not technically contradictory, each claim may be dependent on other claims that were not dependent at the time of application. That is, the technologies of each claim can be combined in various ways as follows: (Item 1) An inkjet water-based ink used to form an image on a fabric material, Pigments and Binder and, Crosslinking agent and wax particles and Equipped with, The binder contains an acrylic resin, The crosslinking agent comprises at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound. The ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.05 or more. The aforementioned wax particles are anionic, water-based ink for inkjet recording. (Item 2) The aforementioned wax particles form aggregates when dropped into a 0.05% by mass aqueous calcium solution, as described in item 1, for the water-based inkjet recording ink. (Item 3) The acrylic resin does not form aggregates when dropped into a 0.05% by mass aqueous calcium solution, and is an aqueous ink for inkjet recording as described in item 1 or 2. (Item 4) An aqueous inkjet recording ink according to any one of items 1 to 3, wherein the ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.27 or less. (Item 5) An inkjet water-based ink for recording according to any one of items 1 to 4, wherein the ratio of the content of wax particles to the content of the binder is 0.14 or more. (Item 6) An aqueous inkjet recording ink according to any one of items 1 to 5, wherein the ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.25 or less. (Item 7) The crosslinking agent comprises an oxazoline group-containing compound, An aqueous inkjet recording ink according to any one of items 1 to 6, wherein the ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.09 or more. (Item 8) The aforementioned crosslinking agent is water-soluble, An inkjet water-based ink for recording according to any one of items 1 to 7, wherein the ratio of the content of wax particles to the content of the binder is 0.50 or less. (Item 9) An inkjet water-based ink for recording according to any one of items 1 to 8, wherein the ratio of the content of wax particles to the content of the binder is 0.20 or more. (Item 10) The aforementioned wax particles comprise at least one of polyethylene wax, oxidized polyethylene wax, and paraffin wax, as described in any one of items 1 to 9, for use as an aqueous inkjet recording ink. (Item 11) A water-based inkjet recording ink described in any of items 1 through 10, A cationic pretreatment solution applied to the fabric material before forming an image on the fabric material using the aforementioned water-based inkjet recording ink, An ink set equipped with this feature. (Item 12) An inkjet recording apparatus comprising an ink storage section, an ink ejection section, and an aqueous inkjet recording ink stored in the ink storage section, wherein the aqueous inkjet recording ink is ejected from the ink ejection section to form an image on a fabric material, The aforementioned water-based inkjet recording ink is Pigments and Binder and, Crosslinking agent and wax particles and Equipped with, The binder contains an acrylic resin, The crosslinking agent comprises at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound. The ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.05 or more. The aforementioned wax particles are anionic. Inkjet recording device. (Item 13) An image forming method for forming an image on a fabric material using an inkjet recording method, A pretreatment step comprising applying a cationic pretreatment solution to the fabric material, wherein the pretreatment solution is applied within the area where an image is formed by an aqueous ink for inkjet recording, An image forming step in which an image is formed on the pre-treated fabric material using the water-based inkjet recording ink, A drying step in which the water-based ink for inkjet recording is dried by heating the fabric material on which the image has been formed, Equipped with, The aforementioned water-based inkjet recording ink comprises a pigment, a binder, a crosslinking agent, and wax particles. The binder contains an acrylic resin, The crosslinking agent comprises at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound. The ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.05 or more. The aforementioned wax particles are anionic. Image forming method. (Item 14) The image forming method according to item 13, wherein in the drying step, the heating temperature is above the melting point of the wax particles and below (the melting point of the wax particles + 50°C). [Explanation of Symbols]

[0124] 10: Inkjet recording device, 11: Storage tank, 12: Carriage, 13: Discharge head, 14: Conveyor roller, 15: Guide rail, 16: Sub-tank, 20: Control unit, 22: Pretreatment liquid coating device, 30: Fabric material

Claims

1. An inkjet water-based ink used to form an image on a fabric material, Pigments and Binder and, Crosslinking agent and wax particles and Equipped with, The binder contains an acrylic resin, The crosslinking agent comprises at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound. The ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.05 or more. The aforementioned wax particles are anionic. Water-based ink for inkjet recording.

2. The aqueous inkjet recording ink according to claim 1, wherein the wax particles form aggregates when dropped into a 0.05% by mass aqueous calcium solution.

3. The acrylic resin does not form aggregates when dropped into a 0.05% by mass aqueous calcium solution, as described in claim 2.

4. The aqueous inkjet recording ink according to claim 3, wherein the ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.27 or less.

5. The aqueous inkjet recording ink according to claim 4, wherein the ratio of the content of wax particles to the content of the binder is 0.14 or more.

6. The aqueous inkjet recording ink according to claim 5, wherein the ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.25 or less.

7. The crosslinking agent comprises an oxazoline group-containing compound, The aqueous inkjet recording ink according to claim 6, wherein the ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.09 or more.

8. The aforementioned crosslinking agent is water-soluble, The water-based inkjet recording ink according to claim 7, wherein the ratio of the content of wax particles to the content of the binder is 0.50 or less.

9. The aqueous inkjet recording ink according to claim 8, wherein the ratio of the content of wax particles to the content of the binder is 0.20 or more.

10. The aqueous inkjet recording ink according to claim 1, wherein the wax particles include at least one of polyethylene wax, oxidized polyethylene wax, and paraffin wax.

11. An aqueous inkjet recording ink according to any one of claims 1 to 10, A cationic pretreatment solution applied to the fabric material before forming an image on the fabric material using the aforementioned water-based inkjet recording ink, An ink set equipped with this feature.

12. An inkjet recording apparatus comprising an ink storage section, an ink ejection section, and an aqueous inkjet recording ink stored in the ink storage section, wherein the aqueous inkjet recording ink is ejected from the ink ejection section to form an image on a fabric material, The aforementioned water-based inkjet recording ink is Pigments and Binder and, Crosslinking agent and wax particles and Equipped with, The binder contains an acrylic resin, The crosslinking agent comprises at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound. The ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.05 or more. The aforementioned wax particles are anionic. Inkjet recording device.

13. An image forming method for forming an image on a fabric material using an inkjet recording method, A pretreatment step comprising applying a cationic pretreatment solution to the fabric material, wherein the pretreatment solution is applied within the area where an image is formed by an aqueous ink for inkjet recording, An image forming step in which an image is formed on the pre-treated fabric material using the water-based inkjet recording ink, A drying step in which the water-based ink for inkjet recording is dried by heating the fabric material on which the image has been formed, Equipped with, The aforementioned water-based inkjet recording ink comprises a pigment, a binder, a crosslinking agent, and wax particles. The binder contains an acrylic resin, The crosslinking agent comprises at least one of an oxazoline group-containing compound and a carbodiimide group-containing compound. The ratio of the content of the crosslinking agent to the total amount of the binder, the crosslinking agent, and the wax particles is 0.05 or more. The aforementioned wax particles are anionic. Image forming method.

14. The image forming method according to claim 13, wherein in the drying step, the heating temperature is above the melting point of the wax particles and below (the melting point of the wax particles + 50°C).

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