Aqueous inkjet ink, and method for printing fiber structure by inkjet method

Abstract

The purpose of the present invention is to provide an aqueous inkjet ink suitable for inkjet printing of a structure comprising cotton or synthetic fibers. Another purpose of the present invention is to provide a method for printing a fiber structure by an ink jet method, which has excellent optical density (OD), penetration suppression, or color rendering properties after printing. This aqueous inkjet ink (1) contains at least a pigment, a dispersant, a solvent, and water. (2) the dispersant is a cationic dispersant having an amine value of 10 mgKOH / g or more and an amine value higher than an acid value; (3) the content of the pigment is from 0.01% by mass to 30% by mass (inclusive); (4) the value of dispersant content / pigment content * 100 is from 5 to 200 (inclusive); and (5) an ink for printing a structure comprising cotton or synthetic fibers.

Description

[0001] This application is a divisional application of the patent application for which the application number is 202180060799.1 (the international application number is PCT / JP2021 / 025733), the application date is July 8, 2021, and the invention name is “Aqueous inkjet ink, method for printing a fibrous structure by an inkjet method”. TECHNICAL FIELD

[0002] The present invention relates to an aqueous inkjet ink for a cotton or synthetic fibrous structure. In addition, the present invention relates to a method for anionizing a fibrous structure and printing by an inkjet method. BACKGROUND

[0003] Image recording methods for forming an image on a recording medium such as paper include an electrophotographic method, a sublimation type and a melt thermal transfer method, an inkjet method, and the like. Among these, the printing device of the inkjet method is inexpensive, and does not require plate making at the time of printing. In addition, it is only necessary to discharge an ink composition at a necessary image portion on a recording medium to directly form an image, so the ink composition can be used efficiently, and in particular, the running cost is low at the time of small-lot production.

[0004] Inkjet inks include dye inks and pigment inks. When a pigment ink is used, the color tone and sharpness are generally inferior compared to when a dye ink is used, but the light resistance and water resistance of the pigment itself are excellent. In addition, inkjet dyeing using a pigment ink also has the advantage that it does not require complicated post-treatment of the cloth compared to when a dye ink is used. For this reason, at present, inkjet printing methods using a pigment ink are attracting attention as a printing method for fibrous structures such as clothes.

[0005] As inkjet dyeing methods using a pigment ink, there are known a method of dyeing a cloth containing at least one of a water-soluble metal salt and a cationic compound, a nonionic water-soluble polymer, and a nonionic surfactant or an amphoteric surfactant (Patent Literature 1); a method of dyeing a cloth treated with a cationic resin and a divalent or trivalent metal ion with a pigment ink (Patent Literature 2); a method of dyeing a cloth to which a hydrophobic low-molecular compound and a cationic resin are applied with a pigment ink, and performing heat treatment to form a film (Patent Literature 3); and the like. The purpose of these methods is to improve the sharpness, water resistance, rubbing resistance, and the like of a printed image.

[0006] Patent Literature 4 discloses an aqueous pigment dispersion having low viscosity and excellent storage stability, and an aqueous inkjet ink having excellent hiding property, using titanium oxide as a pigment. The aqueous pigment dispersion of Patent Literature 4 uses titanium oxide whose surface is treated with an organic compound (any one of a polyol, an alkanolamine or a derivative thereof, an organosilicon compound, a higher fatty acid or a metal salt thereof, and an organometallic compound).

[0007] Patent Document 5 discloses a non-aqueous white ink for active energy ray curable inkjet printing, comprising titanium dioxide, a pigment dispersant, and a polymerizable compound. In Patent Document 5, titanium dioxide that has been surface-treated with silica is preferably used as the titanium dioxide.

[0008] Existing technical documents: Patent documents: Patent Document 1: Japanese Patent Application Publication No. 7-119047; Patent Document 2: Japanese Patent Application Publication No. 2000-226781; Patent document 3: Japanese Patent Application Publication No. 2001-140174; Patent document 4: Japanese Patent No. 5998747; Patent document 5: International Publication No. 2014 / 175440. Summary of the Invention

[0009] The problem the invention aims to solve: However, when printing on fibrous structures such as T-shirts, fabrics, or flags using water-based inkjet inks and inkjet printing, the optical density (OD) is worse than when printing on printing paper, even when using the same water-based inkjet inks. This problem is particularly pronounced when printing on synthetic fiber structures such as polyester.

[0010] Furthermore, white water-based inkjet inks typically use titanium dioxide as the white pigment, but even when using titanium dioxide surface-treated with organic compounds, stability and dispersibility are difficult to ensure in water-based inks. Additionally, when printing on fibrous structures, there is a challenge in adequately covering the fiber colors.

[0011] The purpose of this invention is to provide a water-based inkjet ink suitable for inkjet printing structures made of cotton or synthetic fibers. Furthermore, the purpose of this invention is to provide a method for printing fibrous structures using inkjet technology that exhibits excellent OD (exposure time), penetration inhibition, or color development after printing.

[0012] Solution methods: The inventors have been researching water-based inkjet inks for printing on fibrous structures, especially those made of polyester fibers, using inkjet printing. They have discovered that by combining pigments and dispersants with cationic functional groups in a specific ratio, it is possible to obtain prints with excellent OD values ​​after printing on anionized structures, thus completing this invention.

[0013] Furthermore, to solve the aforementioned problems, the inventors conducted continuous research on white water-based inkjet inks containing titanium dioxide as a white pigment. They discovered that by combining surface-treated titanium dioxide as the white pigment with a cationic dispersant having specific amine and acid values ​​in a specific ratio, the stability and dispersibility of the white pigment could be improved. In addition, the inventors found that using such a white water-based inkjet ink could produce printed materials with excellent opacity (color development) after printing on fibrous structures, thus completing this invention.

[0014] Specifically, this invention relates to a water-based inkjet ink. It is a water-based inkjet ink that contains at least pigments, dispersants, solvents, and water. The dispersant is a cationic dispersant with an amine value of 10 mg KOH / g or higher, and whose amine value is higher than its acid value. The pigment content is between 0.01% and 30% by mass. The value of the ratio of the dispersant content to the pigment content × 100 is between 5 and 200. It is an ink used for printing on structures made of cotton or synthetic fibers.

[0015] The water-based inkjet ink of the present invention, by combining pigments with a dispersant having cationic functional groups, can improve pigment dispersibility and increase the OD (dispersive end effector) after printing. Furthermore, it can suppress printing penetration.

[0016] Preferably, the dispersant is a cationic dispersant with an amine value of 60 mg KOH / g or more and 150 mg KOH / g or less, and an acid value of 0 mg KOH / g. Here, "acid value of 0 mg KOH / g" means not only the case where the acid value is 0 mg KOH / g, but also the case where it is below the detection limit in conventional acid value determination methods.

[0017] Preferably, the synthetic fiber is polyester fiber.

[0018] Preferably, the polyester fiber is anion-treated polyester fiber.

[0019] Preferably, for colored or black pigments, the pigment is any one of Pigment Yellow 155, Pigment Red 122, Pigment Blue 15:3, or Pigment Black 7.

[0020] Preferably, for white pigments, the pigment is titanium dioxide that has been surface-treated with alumina, silica, polyols and / or polysiloxanes.

[0021] In white water-based inkjet inks containing titanium dioxide as a white pigment, using only the surface-treated titanium dioxide disclosed in Patent Documents 4 or 5 cannot improve the stability and dispersibility of the titanium dioxide particles. Furthermore, depending on the type of dispersant used, insufficient color development (occlusion) may occur when printing on fibrous structures. However, white water-based inkjet inks containing specific surface-treated titanium dioxide and specific cationic dispersants in specific proportions exhibit excellent color development (occlusion) even when printing on fibrous structures, and the stability and dispersibility of the titanium dioxide particles in the white water-based inkjet ink should also be excellent.

[0022] Preferably, in the case of water-based inkjet ink containing white pigment, the concentration of dispersant (mass%) / concentration of titanium dioxide (mass%) × amine value (mgKOH / g) in the water-based inkjet ink is 2.50 to 8.50.

[0023] In addition, the present invention relates to a method, It is a method of printing on fibrous structures made of synthetic fibers using inkjet printing. The method has the following characteristics: Step A involves anionizing the fiber structure with an anionizing agent; and Following step A, step B involves printing the fibrous structure using water-based inkjet ink and an inkjet printing method. The water-based inkjet ink contains at least pigments, dispersants, solvents, and water. The dispersant is a cationic dispersant with an amine value of 10 mg KOH / g or higher, and whose amine value is higher than its acid value. The pigment content is between 0.01% and 30% by mass. The value of the dispersant content / pigment content × 100 is more than 5 and less than 200.

[0024] In addition, the present invention relates to a method, It is a method of printing on fibrous structures made of cotton using inkjet printing. The method has the following characteristics: Process B involves printing fibrous structures using water-based inkjet inks and an inkjet printing method. The water-based inkjet ink contains at least pigments, dispersants, solvents, and water. The dispersant is a cationic dispersant with an amine value of 10 mg KOH / g or higher, and whose amine value is higher than its acid value. The pigment content is between 0.01% and 30% by mass. The value of the dispersant content / pigment content × 100 is more than 5 and less than 200.

[0025] Invention effects: According to the present invention, especially when inkjet printing is performed on anionized synthetic fiber structures in color or black, the OD of the printed material can be improved and penetration can be prevented.

[0026] Furthermore, according to the present invention, the stability and dispersibility of pigment particles can be improved in white water-based inkjet inks containing surface-treated titanium dioxide particles as white pigments. According to the present invention, in particular, when inkjet printing is performed on anionized synthetic fiber structures using white pigments, the color development after printing can be improved. Detailed Implementation

[0027] The following describes embodiments of the present invention.

[0028] [pigment] There are no particular limitations on the colored or black pigments that can be used in this invention. For example, carbon black, titanium black, CI No. PY-1, PY-3, PY-12, PY-13, PY-14, PY-17, PY-24, PY-34, PY-55, PY-62, PY-74, PY-79, PY-81, PY-83, PY-87, PY-93, PY-94, PY-97, PY-108, PY-109, PY-110, PY-120, PY-128, PY-129, PY-130, PY- 133.PY-136,PY-138,PY-139,PY-147,PY-150,PY-151,PY-152,PY-154,PY-155,PY-156,PY-165,PY-167,PY-168,PY-1 69. PY-170, PY-173, PY-175, PY-180, PY-183, PY-184, PY-185, PY-191, PY-193, PR-2, PR-5, PR-8, PR-9, PR-15, PR-17, PR -22, PR-23, PR-48:1, PR-48:2, PR-48:3, PR-48:4, PR-53:1, PR-57:1, PR-58:4, PR-63:2, PR-104, PR-112, PR-122, PR-1 44. PR-146, PR-149, PR-150, PR-151, PR-166, PR-168, PR-170, PR-171, PR-176, PR-177, PR-185, PR-220, PR-222, PR-237 The pigments include, but are not limited to, PR-238, PR-239, PR-240, PR-254, PR-264, PB-15:1, PB-15:3, PB-15:4, PB-15:6, PB-16, PB-60, PV-1, PV-19, PV-23, PV-29, PV-32, PV-37, PG-7, PG-36, PO-13, PO-16, PO-34, PO-36, PO-38, PO-43, PO-61, PO-62, PO-64, PO-71, and PO-73. These pigments can be used alone or in combination of two or more.

[0029] The average particle size (average particle size of primary particles) of the colored or black pigments in the water-based inkjet ink of the present invention is preferably 10 to 250 nm, based on the viewpoints of the settling properties of the colored or black pigment particles and the optical density of the printed matter. If the average particle size is less than 10 nm, it is difficult to ensure the dispersion stability of the ink. On the other hand, if the particle size exceeds 250 nm, it is easy to cause the pigment particles to settle.

[0030] Furthermore, the average particle size mentioned here refers to the average of the major and minor diameters when observing more than 100 pigment particles using a transmission electron microscope (the average of the measured number of particles, where the major diameter (nm) of 1 particle is equal to the minor diameter (nm) of 2). The same applies to the average particle size of surface-treated titanium dioxide, which will be discussed later.

[0031] The white pigment that can be used in this invention is titanium dioxide that has been surface-treated with alumina, silica, polyol and / or polysiloxane.

[0032] Both anatase and rutile titanium oxide can be used, but rutile titanium oxide, which has higher opacity for printed materials, is preferred. Alternatively, titanium oxide prepared by known methods such as the chlorination or sulfuric acid process can be used, but titanium oxide prepared by the chlorination process, which has higher whiteness, is preferred.

[0033] Untreated titanium dioxide has numerous hydroxyl groups on its surface, which are the reason for its hydrophilicity. These hydroxyl groups are removed from the titanium dioxide surface by reacting them with polyols or polysiloxanes, which are organic compounds, and then coated with the polyols or polysiloxanes, thereby making the titanium dioxide hydrophobic.

[0034] In Patent Document 4, the organic compound used for surface treatment of titanium dioxide is not particularly limited as long as it can make titanium dioxide hydrophobic. Examples include polyols, alkanolamines or their derivatives, organosilicon compounds, higher fatty acids or their metal salts, organometallic compounds, etc.

[0035] Furthermore, Patent Document 4 discloses a method for surface treatment of titanium oxide using inorganic compounds, in addition to surface treatment with organic compounds, to improve weather resistance and dispersion stability. Examples of inorganic compounds include compounds of silicon, aluminum, zirconium, tin, antimony, and titanium.

[0036] On the other hand, the surface-treated titanium dioxide used in this invention is titanium dioxide that has been surface-treated by three components: (1) aluminum oxide, (2) silicon dioxide, and (3) polyols and / or polysiloxanes of organic compounds.

[0037] The average particle size (average particle size of primary particles) of the surface-treated titanium dioxide in the water-based inkjet ink of the present invention is preferably 100 to 400 nm, based on the viewpoints of the sedimentation properties of the surface-treated titanium dioxide particles and the opacity of the printed matter. If the average particle size is less than 100 nm, it is not easy for titanium dioxide to settle, but the opacity decreases, reducing its practicality as a white inkjet ink. On the other hand, if it exceeds 400 nm, the opacity is sufficient, but sedimentation is easily caused. The average particle size of the surface-treated titanium dioxide is more preferably 150 to 350 nm, and even more preferably 200 to 300 nm.

[0038] [Dispersant] The dispersant used in this invention is a cationic dispersant with an amine value of 10 mg KOH / g or higher, and an amine value higher than its acid value. Preferably, the dispersant has an amine value of 10 mg KOH / g or higher and an acid value of 0, more preferably an amine value of 60 mg KOH / g or higher but less than 150 mg KOH / g and an acid value of 0 mg KOH / g. One dispersant can be used alone, or two or more can be used in combination.

[0039] Here, the amine value refers to the amine value per 1g of dispersant solids, which is the value obtained by potentiometric titration with 0.1N hydrochloric acid aqueous solution and converted to the equivalent of potassium hydroxide (unit: mgKOH / g). Additionally, the acid value refers to the acid value per 1g of dispersant solids, which can be determined by potentiometric titration according to JIS K 0070 (1992) (unit: mgKOH / g).

[0040] There are many cationic dispersants on the market with an amine value of 10 mg KOH / g or higher, and whose amine value is higher than their acid value. Examples include DISPERBYK-182, 183, 184, 185, 191, 2013, 2050, 2070, 2055, BYKJET-9151, 9152, 9171 (all manufactured by BYK JAPAN), EFKA PX-4330, 4350, 4701, 4703, 4733, 4753, 4780 (all manufactured by BASF), and TEGO Dispers 650 (manufactured by Evonik). These dispersants can be used alone or in combination of two or more.

[0041] In this invention, the value of (dispersant concentration (mass%) / titanium dioxide concentration (mass%)) × amine value (mgKOH / g) in the white water-based inkjet ink is preferably 2.50 to 8.50, more preferably 3.20 to 8.20, and even more preferably 3.20 to 7.00. Here, "dispersant concentration (mass%)" refers to the concentration of the solid form of the dispersant contained in the water-based inkjet ink. Furthermore, "titanium dioxide concentration (mass%)" refers to the concentration of surface-treated titanium dioxide contained in the water-based inkjet ink.

[0042] The solvents that can be used in this invention are not particularly limited. For example, monohydric alcohols such as methanol, ethanol, and isopropanol; polyhydric alcohols; ketones or ketols such as acetone and diacetone alcohol; and cyclic ethers such as tetrahydrofuran and dioxane can be used.

[0043] The water-based inkjet ink of the present invention may also contain additives such as pH adjusters, surfactants, chelating agents, rust inhibitors, antioxidants, ultraviolet absorbers, preservatives, antifungal agents, and defoamers, as needed. The content (concentration) of these additives can be adjusted within the range that allows them to perform their functions.

[0044] The pH adjuster that can be used in this invention is not particularly limited. Examples include hydroxides of alkali metals such as sodium oxide, potassium hydroxide, and lithium hydroxide; tertiary amines such as triethanolamine, diethanolamine, dimethylethanolamine, and diethylethanolamine; and ammonia, hydrochloric acid, acetic acid, and formic acid.

[0045] The surfactants that can be used in this invention are not particularly limited, and examples include anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, fluorinated surfactants, and organosilicon surfactants.

[0046] The water-based inkjet ink of the present invention can be obtained by preparing a pigment dispersion (pigment dispersion) and mixing it with solvents and additives. The pigment dispersion can be obtained by mixing pigments and dispersions and dispersing them using a sand mill (bead mill), roller mill, ball mill, paint mixer, ultrasonic disperser, high-pressure emulsifier, etc.

[0047] The water-based inkjet ink of the present invention can be obtained by preparing a pigment dispersion (pigment dispersion), adding solvents and additives to it, and mixing them. The pigment dispersion can be prepared by mixing pigments and dispersions, and then dispersing them using a sand mill (bead mill), roller mill, ball mill, paint mixer, ultrasonic disperser, high-pressure emulsifier, or the like.

[0048] As an example, the dispersion process using a sand mill is described. First, beads containing pigment, dispersant, and dispersion medium are loaded into the sand mill. Glass beads or zirconia beads with a particle size of 0.01–1 mm can be used as beads. The amount of beads used is preferably 2–6 by weight relative to 1 pound of ink. Then, the sand mill is operated for dispersion treatment. The dispersion treatment conditions are preferably at approximately 1000–2000 rpm for 1–20 hours. After dispersion treatment, the beads and other particles are removed by filtration to obtain a pigment dispersion.

[0049] The pigment concentration (mass %) in the water-based inkjet ink of the present invention is preferably 0.01% to 30% by mass and more preferably 0.01% to 20% by mass and even more preferably 1% to 15% by mass and less for any of the colored, black, or white pigments. Within this range, sufficient color development (coverage) can be obtained, and the ink also tends to have excellent storage stability.

[0050] The pH of water-based inkjet ink is preferably 3 to 11, more preferably 4 to 10. Within this range, the ink not only has excellent storage stability, but also can suppress damage to the ejector device or fiber structure.

[0051] <Preparation of Water-Based Inkjet Ink 1: Color or Black> (Example 1 / Cyan Ink) 15.0 parts by weight of CYANINE BLUE KRO (PB-15:3, manufactured by Sanyo Shiki Co., Ltd.) as cyan pigment, 11.5 parts by weight of dispersant C (DISPERBYK-185 (manufactured by BYK JAPAN Co., Ltd. / amine value = 17 mg KOH / g, active ingredient 52%) as dispersant), 73.5 parts by weight of deionized water, and 400 parts by weight of zirconia beads with a diameter of 0.5 mm were loaded into a sand mill and dispersed at 1,500 rpm for 3 hours. Afterward, the zirconia beads were removed to obtain a pigment dispersion. In addition, the particle size of the pigment and dispersant was adjusted to about 100-110 nm.

[0052] In this pigment dispersion, as shown in Table 1, a cyan ink with pH 9 was prepared by mixing BYK-348 (a polyether-modified siloxane manufactured by BYK JAPAN) as a surfactant, formic acid or triethanolamine as a pH adjuster, 1,2-hexanediol as a solvent, glycerol, and deionized water. Additionally, the aqueous inkjet inks of Examples 1-11 and Comparative Examples 1-10 were prepared in total quantities of 100.0 parts by weight.

[0053] [Table 1] .

[0054] (Example 2 / Magenta Ink) Except for the use of FASTOGEN SUPER MAGENTA RG (DIC PR-122) as a magenta pigment, the magenta ink was prepared in the same manner as in Example 1.

[0055] (Example 3 / Yellow Ink) Except for the use of Inkjet Yellow 4GC (Clariant PY-155) as a yellow pigment, the yellow ink was prepared in the same manner as in Example 1.

[0056] (Example 4 / Black Ink) Except for the use of NIPex 160IQ (carbon black from Orion Engineered Carbons) as the black pigment, the black ink was prepared in the same manner as in Example 1.

[0057] (Example 5 / Cyan Ink) Except for using 6.0 parts by weight of dispersant D (EFKA PX4701 (BASF, amine value = 40 mg KOH / g, 100% active ingredient) as a dispersant) and making deionized water 79.0 parts by weight, the cyan ink was prepared in the same manner as in Example 1.

[0058] (Example 6 / Cyan Ink) Except for using 6.0 parts by weight of dispersant E (BYKJET-9151 (BYK JAPAN Corporation / amine value = 18 mg KOH / g, acid value = 8 mg KOH / g, active ingredient 100%)) as a dispersant and making deionized water 79.0 parts by weight, the cyan ink was prepared in the same manner as in Example 1.

[0059] (Example 7 / Cyan Ink) Except for using 6.0 parts by weight of dispersant I (BYKJET-9152 (BYK JAPAN Co., Ltd. / amine value = 19 mg KOH / g, acid value = 6 mg KOH / g, active ingredient 100%)) as a dispersant and making deionized water 79.0 parts by weight, the cyan ink was prepared in the same manner as in Example 1.

[0060] (Example 8 / Cyan Ink) Except for using 8.7 parts by weight of dispersant C and 76.3 parts by weight of deionized water, the cyan ink was prepared in the same manner as in Example 1.

[0061] (Example 9 / Cyan Ink) Except for using 17.3 parts by weight of dispersant C and 67.7 parts by weight of deionized water, the cyan ink was prepared in the same manner as in Example 1.

[0062] (Example 10 / Cyan Ink) Except for using 37.5 parts by weight of dispersant A (amine value 67 mg KOH / g, solids 20%) as a dispersant, and making deionized water 47.5 parts by weight, the cyan ink was prepared in the same manner as in Example 1.

[0063] (Example 11 / Cyan Ink) Except for using 37.5 parts by weight of dispersant B (amine value 135 mg KOH / g, solids 20%) as a dispersant, and making deionized water 47.5 parts by weight, the cyan ink was prepared in the same manner as in Example 1.

[0064] [Preparation method of dispersant A] A resin with a monomer composition ratio of benzyl methacrylate / dimethylaminoethyl methacrylate = 80 / 20 (mass ratio) and an amine value of 67 mg KOH / g was prepared. Formic acid and deionized water were added to the resin to dissolve it, and the solids content was adjusted to 20% to obtain dispersant A.

[0065] [Preparation method of dispersant B] A resin with a monomer composition ratio of benzyl methacrylate / dimethylaminoethyl methacrylate = 60 / 40 (mass ratio) and an amine value of 135 mg KOH / g was prepared. Formic acid and a deionized solution were added to this resin to adjust the solids content to 20%, thus obtaining dispersant B.

[0066] (Comparative Example 1 / Cyan Ink) Except that the amount of dispersant F (DISPERBYK-190 (BYK JAPAN Co., Ltd. / acid value = 10 mg KOH / g, active ingredient 40%)) was 15.0 parts by weight and the amount of deionized water was 70.0 parts by weight, the cyan ink was prepared in the same manner as in Example 1.

[0067] (Comparative Example 2 / Cyan Ink) Except that dispersant J (Joncryl 63J (BASF product / acid value = 213 mg KOH / g, active ingredient 30%)) was used as 20.0 parts by weight and deionized water was used as 65.0 parts by weight, the cyan ink was prepared in the same manner as in Example 1.

[0068] (Comparative Example 3 / Magenta Ink) Except that dispersant F is used as a dispersant in a quantity of 15.0 parts by weight and deionized water is used in a quantity of 70.0 parts by weight, the magenta ink was prepared in the same manner as in Example 2.

[0069] (Comparative Example 4 / Magenta Ink) Except that dispersant J is used in a quantity of 20.0 parts by weight and deionized water is used in a quantity of 65.0 parts by weight, the magenta ink was prepared in the same manner as in Example 2.

[0070] (Comparative Example 5 / Yellow Ink) Except that the amount of dispersant F as a dispersant is 15.0 parts by weight and the amount of deionized water is 70.0 parts by weight, the yellow ink was prepared in the same manner as in Example 3.

[0071] (Comparative Example 6 / Yellow Ink) Except that dispersant J is used in a quantity of 20.0 parts by weight and deionized water is used in a quantity of 65.0 parts by weight, the yellow ink was prepared in the same manner as in Example 3.

[0072] (Comparative Example 7 / Black Ink) Except that dispersant F is used in a quantity of 15.0 parts by weight and deionized water is used in a quantity of 70.0 parts by weight, the black ink was prepared in the same manner as in Example 4.

[0073] (Comparative Example 8 / Black Ink) Except that dispersant J is used in a quantity of 20.0 parts by weight and deionized water is used in a quantity of 65.0 parts by weight, the black ink was prepared in the same manner as in Example 4.

[0074] (Comparative Example 9 / Cyan Ink) Except for using 7.5 parts by weight of dispersant G (DISPERBYK-180 (BYK JAPAN, amine value 94 mg KOH / g, acid value 94 mg KOH / g, active ingredient 100%)) as a dispersant and making deionized water 77.5 parts by weight, the cyan ink was prepared in the same manner as in Example 1.

[0075] (Comparative Example 10 / Cyan Ink) Except for using 7.5 parts by weight of dispersant H (DISPERBYK-191 (BYK JAPAN, amine value 20 mg KOH / g, acid value 30 mg KOH / g, active ingredient 100%)) as a dispersant and making deionized water 77.5 parts by weight, the cyan ink was prepared in the same manner as in Example 1.

[0076] <Fiber Structure> The following three types of fiber structures were used as printing samples: • The structure of the cotton material: 100% pure cotton fabric (wide-width cotton fabric produced by a dyeing company without mercerizing treatment); • Polyester structure (untreated polyester structure): 100% polyester cotton (Toray Amina); • Anionized polyester structure (anionized polyester structure): A structure that has been treated with an anionizing agent to obtain a structure identical to the polyester structure.

[0077] <Anionization Treatment Method / Process A> A cationic polymer (cationic polymer compound / Sanyo Pigment Co., Ltd., cationic agent CTF1101) was applied as a 6 g / L preparation solution to the polyester structure via 1DIP / 1NIP, and then dried at 130°C for 3 minutes. Next, an anionic polymer was applied as a 60 g / L preparation solution via 1DIP / 1NIP, and then dried at 130°C for 3 minutes to obtain an anionized polyester structure.

[0078] Here, "anionization treatment" in this invention refers to attaching an anionic polymerizing agent to a structure composed of synthetic fibers. The anionic polymerizing agent can be selected from anionic polyester resins, anionic surfactants, polyester emulsions, etc., with polyester emulsions being preferred. Polyester resins that can be used in polyester emulsions include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, referring to substances emulsified with an activator.

[0079] Furthermore, preferably, prior to such treatment, the polymer is first cationicized using a cationic polymerizing agent. Here, known polymers (polymers or prepolymers) containing tertiary amino or quaternary ammonium groups or both can be used as cationic polymerizing agents. In addition, cationic compounds generally used as cationic agents can also be used.

[0080] Examples of polymers containing tertiary amino groups include: (a) polymers of alkylaminoalkyl (meth)acrylamides, such as dimethyl or diethylaminoethyl (meth)acrylamide, dimethyl or diethylaminopropyl (meth)acrylamide, etc.; (b) polymers of dialkylaminoalkyl (meth)acrylates, such as dimethyl (meth)acrylate or diethylaminoethyl acrylate, dimethyl (meth)acrylate or diethylaminopropyl acrylate, etc.; (c) acrylamide-styrene copolymers; and (d) urethane polymers containing tertiary amino groups, etc.

[0081] Examples of polymers containing quaternary ammonium groups include: (e) polymers of (meth)acryloyloxyalkyl trialkylammonium salts, such as polymers of 2-(meth)acryloyloxyethyltrimethylammonium chloride and 3-(meth)acryloyloxy-2-hydroxypropyltrimethylammonium chloride; (f) polymers of (meth)acrylamide alkyl trialkylammonium salts, such as polymers of (3-(meth)acrylamidopropyltrimethylammonium chloride) and 3-(meth)acryloylamino-2-hydroxypropyltrimethylammonium chloride; and (g) polymers of 2-(meth)acryloyloxyalkylbenzylammonium salts, such as 2-(meth)acryloyloxyethylbenzylammonium chloride or... Polymers of 2-(meth)acryloyloxyethyl dimethyl benzyl ammonium chloride, copolymers of monomers of acryloyloxyethyl dimethyl benzyl ammonium chloride or 2-(meth)acryloyloxyethyl dimethyl benzyl ammonium chloride with acrylamide, dimethylaminoethyl acrylate, etc.; (h) copolymers of acrylamide propyl dimethyl benzyl chloride with N,N-dimethylacrylamide and N-methyl-N-benzylallylamine salt with N-methyl-N-hydroxyethylaminopropylacrylamide, etc.; (i) other polymers such as dimethyl or diethyldiallyl ammonium chloride, β-vinyloxyethyltrialkylammonium salt, vinylbenzylammonium salt, etc.

[0082] In addition, as cationic compounds, compounds containing quaternary ammonium groups (j) can be used, such as hexamethylene-bis(3-chloro-2-hydroxypropyl-dimethylammonium chloride), trimethylene-bis(3-chloro-2-hydroxypropyl-dimethylammonium chloride), hexamethylene-bis(2,3-epoxypropyl-dimethylammonium chloride), trimethylene-bis(2,3-epoxypropyl-dimethylammonium chloride), 3-chloro-2-hydroxypropyl-trimethylammonium chloride, 2,3-epoxypropyltrimethylammonium chloride, etc., wherein polydialkylamino(meth)acrylate, polydimethyldiallylammonium chloride, and urethane polymers containing tertiary amino groups are preferred.

[0083] Furthermore, the anionization treatment in this invention is not limited to the treatment described in step A below.

[0084] <Printing / Process B of Fiber Structures> Using three types of fiber structures as printing objects, solid images were formed by printing with a 600 dpi inkjet printer using the prepared water-based inkjet ink.

[0085] <OD value measurement method> The optical density of the obtained solid image surface was measured using a GretagMacbeth RD-19 reflectance density meter (SAKATA INX CORPORATION).

[0086] <Infiltration> For the obtained solid image, use a ruler to measure the distance at which the ink bleeds the most.

[0087] For water-based inkjet inks in cyan, magenta, yellow, and black, the results of OD values, OD evaluations, and penetration evaluations are shown in Tables 2 to 5. In Tables 2 to 5, for the OD evaluations of yellow, cyan, and black, OD values ​​of 1.15 or higher are rated as "◎", 1.10 or higher as "○", 1.05 or higher but less than 1.10 as "△", and less than 1.05 as "×". For magenta, OD values ​​of 1.00 or higher are rated as "○", and less than 1.00 as "△". Furthermore, for the penetration evaluation, for all four colors, ink penetration distances less than 1 mm are rated as "○", 1 mm to less than 2 mm as "△", and 2 mm or more as "×". This evaluation is also applied in Tables 6 to 8 described later.

[0088] [Table 2] .

[0089] [Table 3] .

[0090] [Table 4] .

[0091] [Table 5] .

[0092] For the cotton material structure, all colors of the inks using dispersant C (Examples 1-4) received an OD and penetration rating of "○". On the other hand, when dispersant F (Comparative Examples 1, 3, 5, 7) or dispersant J (Comparative Examples 2, 4, 6, 8) were used as dispersants, the OD or penetration rating was "×", indicating a lack of practicality.

[0093] For structures made of untreated polyester, all colors and all dispersants received an OD or penetration rating of "×", indicating a lack of practicality. However, for structures made of anionized polyester (represented as treated polyester in Tables 2-5) that had undergone anionization treatment, all colors of inks using dispersant C (Examples 1-4) received an OD and penetration rating of "○".

[0094] The OD values, OD evaluations, and penetration evaluations of the cyan water-based inkjet printers of Examples 5-7 are shown in Table 6. Examples 5-7, which used dispersants D, E, and I as dispersants for the pigment dispersion, yielded the same results as in Example 1.

[0095] [Table 6] .

[0096] The OD values, OD evaluations, and penetration evaluations of the cyan water-based inkjet printers of Examples 1, 8, and 9 are shown in Table 7. When the value of dispersant content (D) / pigment content (P) × 100 is in the range of 30 to 60, the OD evaluation and penetration evaluation of the cotton or anionized polyester can be determined to be "○".

[0097] [Table 7] .

[0098] The OD values, OD evaluations, and penetration evaluations of the cyan water-based inkjet inks of Examples 10-11 and Comparative Examples 9 and 10 are shown in Table 8. The dispersants used in Examples 10-11, which employed dispersant A and dispersant B, had OD evaluations of "◎" and penetration evaluations of "○", indicating they were the most superior among the examples.

[0099] [Table 8] .

[0100] Thus, it can be determined that the water-based inkjet ink of the present invention, containing pigments and specific cationic dispersants, is suitable for printing fibrous structures made of cotton or anionized polyester fibers, compared with water-based inkjet inks containing the same pigments and other dispersants.

[0101] From Tables 2 to 8, it can be determined that in the case of water-based inkjet inks containing colored or black pigments, the preferred dispersant is a cationic dispersant with an amine value of 10 mg KOH / g or higher and an amine value higher than an acid value. More preferably, it is a cationic dispersant with an amine value of 60 mg KOH / g or higher and 150 mg KOH / g or lower and an acid value of 0 mg KOH / g, such as dispersant A and dispersant B.

[0102] <Preparation of Water-Based Inkjet Ink 2: White> (Example 12) 40.0 parts by weight of TIPAQUE PF-728 (manufactured by Ishihara Sangyo Co., Ltd., treated with alumina / silica / polysiloxane), 20.0 parts by weight of dispersant A, 40.0 parts by weight of deionized water, and 400 parts by weight of 0.5 mm diameter zirconia beads were loaded into a sand mill and dispersed at 1,500 rpm for 2 hours. Afterwards, the zirconia beads were removed to obtain a titanium dioxide dispersion.

[0103] The titanium dioxide dispersion, BYK-348 (a polyether-modified siloxane from BYK Japan) as a surfactant, 1,2-hexanediol as a solvent, glycerol, and deionized water were mixed to prepare the white ink of Example 12. Additionally, the water-based inkjet inks of Examples 12-25 and Comparative Examples 11-27 were adjusted to a total of 100.0 parts by weight.

[0104] [Table 9] .

[0105] (Example 13) Except for using 10.0 parts by weight of dispersant B as a dispersant and making the amount of deionized water 50.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 12. Then, the white ink of Example 13 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0106] (Example 14) Except for using 15.3 parts by weight of dispersant C (DISPERBYK-185, BYK JAPAN, amine value 17 mg KOH / g, solids 52%) as a dispersant and making deionized water 44.7 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 1. Then, the white ink of Example 3 was prepared in the same manner as in Example 1, with the dosages shown in Table 9.

[0107] (Example 15) Except for using 6.0 parts by weight of dispersant D as a dispersant and making the amount of deionized water 54.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 1. Then, the white ink of Example 15 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0108] (Example 16) Except for using 6.0 parts by weight of dispersant E as a dispersant and making the amount of deionized water 54.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 12. Then, the white ink of Example 16 was prepared in the same manner as in Example 1, with the dosages shown in Table 9.

[0109] (Example 17) Except that 40.0 parts by weight of TIPAQUE PF-740 (manufactured by Ishihara Sangyo Co., Ltd., treated with alumina / zirconia / silica / polysiloxane) were used, a titanium oxide dispersion was obtained in the same manner as in Example 12. Then, the white ink of Example 17 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0110] (Example 18) Except that the amount of TIPAQUE PF-740 was 40.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 15. Then, the white ink of Example 18 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0111] (Example 19) Except for using 40.0 parts by weight of TIPAQUE CR-63 (manufactured by Ishihara Sangyo Co., Ltd., treated with alumina / silica / polyol / polysiloxane) as titanium dioxide, the titanium dioxide dispersion was obtained in the same manner as in Example 12. Subsequently, the white ink of Example 19 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0112] (Example 20) Except for the use of 40.0 parts by weight of TIPAQUE CR-63 as titanium oxide, the titanium oxide dispersion was obtained in the same manner as in Example 15. Subsequently, the white ink of Example 20 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0113] (Example 21) Except for using 40.0 parts by weight of TIPAQUE PF-671 (manufactured by Ishihara Sangyo Co., Ltd., treated with alumina / silica / polyol) as titanium dioxide, the titanium dioxide dispersion was obtained in the same manner as in Example 12. Then, the white ink of Example 21 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0114] (Example 22) Except for the use of 40.0 parts by weight of TIPAQUE PF-671 as titanium oxide, the titanium oxide dispersion was obtained in the same manner as in Example 15. Subsequently, the white ink of Example 22 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0115] (Example 23) Except that dispersant A was 10.0 parts by weight and deionized water was 50.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 12. Then, the white ink of Example 23 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0116] (Example 24) Except that the amount of dispersant B was 6.0 parts by weight and the amount of deionized water was 54.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 13. Then, the white ink of Example 13 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0117] (Example 25) Except that the dispersant D was 8.0 parts by weight and the deionized water was 52.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 15. Then, the white ink of Example 25 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0118] (Comparative Example 11) Except for using 40.0 parts by weight of TIPAQUE PF-726 (manufactured by Ishihara Sangyo Co., Ltd., treated with alumina / silica) as titanium dioxide, a titanium dioxide dispersion was obtained in the same manner as in Example 12. Subsequently, white ink of Comparative Example 11 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0119] (Comparative Example 12) Except for the use of 40.0 parts by weight of TIPAQUE PF-726 as titanium oxide, a titanium oxide dispersion was obtained in the same manner as in Example 13. Subsequently, the white ink of Comparative Example 12 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0120] (Comparative Example 13) Except for the use of 40.0 parts by weight of TIPAQUE PF-726 as titanium oxide, a titanium oxide dispersion was obtained in the same manner as in Example 14. Subsequently, white ink for Comparative Example 13 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0121] (Comparative Example 14) Except that TIPAQUE PF-726 was used as titanium oxide in a concentration of 40.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 15. Subsequently, the white ink of Comparative Example 14 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0122] (Comparative Example 15) Except for the use of 40.0 parts by weight of TIPAQUE PF-726 as titanium oxide, a titanium oxide dispersion was obtained in the same manner as in Example 16. Subsequently, the white ink of Comparative Example 15 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0123] (Comparative Example 16) Except for the use of 40.0 parts by weight of TIPAQUE CR-50 (manufactured by Ishihara Sangyo Co., Ltd., alumina-treated) as titanium dioxide, a titanium dioxide dispersion was obtained in the same manner as in Example 12. Subsequently, white ink for Comparative Example 16 was prepared in the same manner as in Example 12, using the dosages shown in Table 9.

[0124] (Comparative Example 17) Except for the use of 40.0 parts by weight of TIPAQUE CR-50 as titanium dioxide, the titanium dioxide dispersion was obtained in the same manner as in Example 15. Subsequently, the ink of Comparative Example 17 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0125] (Comparative Example 18) Except for the use of 40.0 parts by weight of TIPAQUE CR-50-2 (manufactured by Ishihara Sangyo Co., Ltd., treated with alumina / polyol) as titanium dioxide, a titanium dioxide dispersion was obtained in the same manner as in Example 12. Subsequently, white ink of Comparative Example 18 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0126] (Comparative Example 19) Except for the use of 40.0 parts by weight of TIPAQUE CR-50-2 as titanium oxide, a titanium oxide dispersion was obtained in the same manner as in Example 15. Subsequently, white ink for Comparative Example 19 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0127] (Comparative Example 20) Except for using 10.0 parts by weight of dispersant F as a dispersant and making the amount of deionized water 50.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 12. Then, the white ink of Comparative Example 20 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0128] (Comparative Example 21) Except for the use of 3.2 parts by weight of dispersant G as a dispersant and the amount of deionized water being 56.8 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 12. Subsequently, the white ink of Comparative Example 21 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0129] (Comparative Example 22) Except for using 6.0 parts by weight of dispersant H as a dispersant and making the amount of deionized water 54.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 12. Then, the white ink of Comparative Example 22 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0130] (Comparative Example 23) Except that dispersant A was 6.0 parts by weight and deionized water was 54.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 12. Then, the white ink of Comparative Example 23 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0131] (Comparative Example 24) Except that dispersant A was 30.0 parts by weight and deionized water was 30.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 1. Then, the white ink of Comparative Example 14 was prepared in the same manner as in Example 1, with the dosages shown in Table 9.

[0132] (Comparative Example 25) Except that dispersant B was 16.0 parts by weight and deionized water was 44.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 13. Then, the white ink of Comparative Example 25 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0133] (Comparative Example 26) Except that the dispersant D was 2.0 parts by weight and the deionized water was 58.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 15. Then, the white ink of Comparative Example 26 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0134] (Comparative Example 27) Except that the dispersant D was 10.0 parts by weight and the deionized water was 50.0 parts by weight, the titanium oxide dispersion was obtained in the same manner as in Example 15. Then, the white ink of Comparative Example 27 was prepared in the same manner as in Example 12, with the dosages shown in Table 9.

[0135] <Stability Test> Take 10g of the white ink from Examples 12-25 and Comparative Examples 10-27 into a sealed container and let it stand for one week in a constant temperature device at 60°C. After cooling to room temperature, use a light scattering spectrophotometer and an E-type viscometer to measure the average particle size (average particle size of titanium oxide particles as pigment) and viscosity of the white ink. The average particle size (average particle size of titanium oxide particles as pigment) and viscosity were also measured before the stability test. Let the average particle size or viscosity before the stability test be (A) and the average particle size or viscosity after the stability test be (B), and calculate the increase rate of the measured values ​​using the following formula: Increase rate (%) = (BA) / A × 100.

[0136] Then, for the calculated increase rate, the stability of each white ink was evaluated based on the following evaluation criteria. Additionally, levels above "△" are considered practically applicable: ○: The increase rate of both average particle size and viscosity is less than 10%; △: The increase rate of either average particle size or viscosity is more than 10%; ×: The increase rate of both average particle size and viscosity is more than 10%.

[0137] <Settlement Test> Take 10g of the white inks from Examples 12-25 and Comparative Examples 10-27 into a glass container and let it stand for 3 days in a constant temperature device at 25°C. Afterwards, evaluate the settling properties of each white ink based on the following evaluation criteria. Additionally, "○" indicates a practical level: ○: No sediment was found at the bottom of the glass container; ×: Settlement was found at the bottom of the glass container.

[0138] <Anionization Treatment Method / Process A> Through step A of the above-mentioned preparation 1 of water-based inkjet ink, an anionized polyester structure was obtained.

[0139] <Printing / Process B of Fiber Structures> For the white inks of Examples 12-25 and Comparative Examples 10-27, solid printing was performed on the following substrates using a printer with a resolution of 600 dpi: Substrate 1: Black cotton fabric (Kurabo H.444). Substrate 2: Black polyester fabric after the above anionization treatment.

[0140] <Coverability Test> For substrate 1 and substrate 2, the OD values ​​of the obtained image surfaces were measured using a reflectance density meter (GretagMacbeth RD-19, SAKATA INXCORPORATION), and the covering power was calculated based on the following formula: Coverage (%) = (1 - OD of printed material / OD of black cotton cloth before printing) × 100.

[0141] Next, the hiding power of each white ink was evaluated based on the following evaluation criteria. Additionally, levels marked "△" and above represent practically applicable levels: ◎: Coverage capacity of over 70%; ○: Coverage capacity is 50% or more but less than 70%; △: Coverage capacity is 30% or more but less than 50%; ×: Coverage capacity is less than 30%.

[0142] Table 10 shows the following for the white inks of Examples 11-25: (1) the content of white pigment, dispersant, and deionized water in the pigment dispersion; (2) the value of (dispersant concentration (mass%) / titanium oxide concentration (mass%)) × amine value (mgKOH / g); and (3) the evaluation results of stability test, sedimentation test, and opacity test. Table 11 shows the following for the white inks of Comparative Examples 10-27: (1) the content of white pigment, dispersant, and deionized water; (2) the value of (dispersant concentration (mass%) / titanium oxide concentration (mass%)) × amine value; and (3) the evaluation results of stability test, sedimentation test, and opacity test.

[0143] [Table 10] .

[0144] [Table 11] .

[0145] According to Table 10, all evaluation items for the white inks of Examples 12-25 were "practical". Furthermore, all evaluation items except for Example 16 were "○" or better. In addition, the stability and sedimentation of Examples 12, 13, 17, 19, 21, 23, and 24 were "○", and their hiding power was "◎", indicating particularly excellent performance. On the other hand, according to Table 11, the white inks of Comparative Examples 10-27 each had one evaluation item marked "×", indicating a lack of practicality.

[0146] Here, in the case of the white ink of Example 12, the dispersant in 25.0 parts by weight of titanium dioxide dispersion is 20.0 × (25 / 100) parts by weight, and the solids of the dispersant are 20.0 × (25 / 100) × 0.2 parts by weight. The titanium dioxide in 25.0 parts by weight of titanium dioxide dispersion is 40.0 × (25 / 100) parts by weight. Since the total amount of white ink is 100 parts by weight, the (dispersant concentration (mass%) / titanium dioxide concentration (mass%)) × amine value (mgKOH / g) in the white ink (water-based inkjet ink) is calculated as 20.0 × (25 / 100) × 0.2 (%) / 40.0 × (25 / 100) (%) × 67 = 6.70. The white inks of other examples and comparative examples are also calculated similarly as (dispersant concentration (mass%) / titanium dioxide concentration (mass%)) × amine value (mgKOH / g).

[0147] From Tables 10 and 11, it can be determined that white inks with excellent stability, settling properties, and hiding power possess the following conditions: (i) titanium dioxide surface-treated with alumina, silica, polyol, and / or polysiloxane is used as the white pigment; (ii) the amine value of the cationic dispersant is 10 mg KOH / g or more, and the amine value is greater than the acid value; (iii) the value of (dispersant concentration (mass%) / titanium oxide concentration (mass%)) × amine value (mg KOH / g) is 2.50 to 8.50. Furthermore, the value of (dispersant concentration (mass%) / titanium oxide concentration (mass%)) × amine value (mg KOH / g) is preferably 3.20 to 8.20, more preferably 3.20 to 7.00. The cationic dispersant is preferably 60 mg KOH / g or more and 150 mg KOH / g or less, and the acid value is 0 mg KOH / g.

[0148] As described above, it can be determined that the water-based inkjet ink of the present invention, containing pigments and specific cationic dispersants, is more suitable for printing fibrous structures made of cotton or anionized polyester fibers compared to water-based inkjet inks containing the same pigments and other dispersants. Furthermore, when the water-based inkjet ink of the present invention contains surface-treated titanium dioxide as a white pigment, the stability and dispersibility of the pigment particles are excellent. Additionally, when printing on fibrous structures, the color of the fibers can be adequately covered.

[0149] Industrial applicability: The water-based inkjet ink and the method for printing fibrous structures by inkjet printing of the present invention are useful in the printing field.

Claims

1. A water-based inkjet ink, It is a water-based inkjet ink that contains at least pigments, dispersants, solvents, and water. The pigment is titanium dioxide that has undergone surface treatment with alumina, silica, polyols and / or polysiloxanes. The dispersant is a cationic dispersant with an amine value of 10 mg KOH / g or higher, and whose amine value is higher than its acid value. The pigment content is between 0.01% and 30% by mass. The value of the ratio of the dispersant content to the pigment content × 100 is between 5 and 200. The concentration of dispersant (mass %) / concentration of titanium dioxide (mass %) × amine value (mgKOH / g) in the water-based inkjet ink is 3.20–8.

20. It is an ink used for printing on structures made of cotton or synthetic fibers.

2. The water-based inkjet ink according to claim 1, characterized in that, The dispersant is a cationic dispersant with an amine value of 60 mg KOH / g or higher and 150 mg KOH / g or lower, and an acid value of 0 mg KOH / g.

3. The water-based inkjet ink according to claim 1 or 2, characterized in that, The synthetic fiber is polyester fiber.

4. The water-based inkjet ink according to claim 3, characterized in that, The polyester fiber is anionized polyester fiber.

5. One method, It is a method of printing on fibrous structures made of synthetic fibers using inkjet printing. The method has the following characteristics: Step A involves anionizing the fiber structure with an anionizing agent, and... Following step A, step B involves printing the fibrous structure using water-based inkjet ink and an inkjet printing method. The water-based inkjet ink contains at least pigments, dispersants, solvents, and water. The pigment is titanium dioxide that has undergone surface treatment with alumina, silica, polyols and / or polysiloxanes. The dispersant is a cationic dispersant with an amine value of 10 mg KOH / g or higher, and whose amine value is higher than its acid value. The pigment content is between 0.01% and 30% by mass. The value of the ratio of the dispersant content to the pigment content × 100 is between 5 and 200. The concentration of dispersant (mass %) / concentration of titanium dioxide (mass %) × amine value (mgKOH / g) in the water-based inkjet ink is 3.20 to 8.

20.

6. One method, It is a method of printing on fibrous structures made of cotton using inkjet printing. The method includes step B, which involves printing a fibrous structure using water-based inkjet ink and an inkjet printing method. The water-based inkjet ink contains at least pigments, dispersants, solvents, and water. The pigment is titanium dioxide that has undergone surface treatment with alumina, silica, polyols and / or polysiloxanes. The dispersant is a cationic dispersant with an amine value of 10 mg KOH / g or higher, and whose amine value is higher than its acid value. The pigment content is between 0.01% and 30% by mass. The value of the ratio of the dispersant content to the pigment content × 100 is between 5 and 200. The concentration of dispersant (mass %) / concentration of titanium dioxide (mass %) × amine value (mgKOH / g) in the water-based inkjet ink is 3.20 to 8.

20.

7. The method according to claim 5 or 6, characterized in that, The dispersant is a cationic dispersant with an amine value of 60 mg KOH / g or higher and 150 mg KOH / g or lower, and an acid value of 0 mg KOH / g.

8. The method according to claim 5, characterized in that, The synthetic fiber is polyester fiber.

9. The method according to claim 5, characterized in that, The anionizing agent is a polyester emulsion.