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

Abstract

To provide an aqueous inkjet ink suitable for inkjet printing of a structure made of cotton or synthetic fiber. Another object of the present invention is to provide a method for printing a fabric structure by an inkjet method, which is excellent in optical density (OD), bleeding suppression, or color development after printing.SOLUTION: The water-based inkjet ink of the present teaching is an ink for printing structures made of cotton or synthetic fibers, in which the water-based inkjet ink (1) contains at least pigments, dispersants, solvents and water, (2) the dispersants have an amine value of not less than 10mgKOH / g, and the amine value is higher than the acid value, (3) the content of the pigments is not less than 0.01% by mass and not more than 30% by mass, and (4) the value of [(content of dispersants) / (content of pigments)] * 100 is not less than 5 and not more than 200.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a water-based inkjet ink for cotton or synthetic fiber structures, and to a method for anionizing a fiber structure and printing the anionized fiber structure by an inkjet method. [Background technology]

[0002] Image recording methods for forming an image on a recording medium such as paper include electrophotography, dye-sublimation and melt-type thermal transfer, and inkjet. Among these, the inkjet method uses inexpensive printing equipment and does not require a printing plate. Furthermore, since the ink composition is ejected only onto the required image area to directly form an image on the recording medium, the ink composition can be used efficiently and running costs are low, especially in small-lot production.

[0003] Inkjet inks include dye inks and pigment inks. Pigment inks are generally inferior in color tone and clarity compared to dye inks, but the pigment itself has excellent lightfastness and water resistance. In addition, inkjet dyeing using pigment inks has the advantage that, compared to dye inks, complicated post-processing of fabrics is not required. For these reasons, inkjet printing methods using pigment inks are currently attracting attention as a method for printing on textile structures such as clothing.

[0004] Known inkjet printing methods using pigment inks include a method of dyeing a fabric containing a water-soluble metal salt, at least one cationic compound, a nonionic water-soluble polymer, and a nonionic surfactant or an amphoteric surfactant (Patent Document 1), a method of dyeing a fabric treated with a cationic resin and a divalent or trivalent metal ion with a pigment ink (Patent Document 2), and a method of dyeing a fabric to which a hydrophobic low-molecular-weight compound and a cationic resin have been applied with a pigment ink and then heat-treating the fabric to form a coating (Patent Document 3).These methods aim to improve the clarity, water resistance, and abrasion resistance of printed images, etc.

[0005] Patent Document 4 discloses an aqueous pigment dispersion that uses titanium oxide as a pigment and has low viscosity and excellent storage stability, and an aqueous inkjet ink that has excellent hiding power. The aqueous pigment dispersion in Patent Document 4 uses titanium oxide whose surface has been treated with an organic compound (any of polyhydric alcohol, alkanolamine or its derivative, organosilicon compound, higher fatty acid or its metal salt, and organometallic compound).

[0006] Patent Document 5 discloses an actinic radiation-curable non-aqueous white ink for inkjet printing, which contains titanium oxide, a pigment dispersant, and a polymerizable compound. Patent Document 5 states that it is preferable to use titanium oxide that has been surface-treated with silica. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 7-119047 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-226781 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-140174 [Patent Document 4] Patent No. 5998747 [Patent Document 5] International Publication No. 2014 / 175440 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0008] However, when water-based inkjet inks are used to print structures made of fibers (fibrous structures) such as T-shirts, textiles, or flags by the inkjet method, there is a problem that the OD (optical density) is inferior compared to when printing on printing paper, even when the same water-based inkjet inks are used. This problem is particularly noticeable when printing structures made of synthetic fibers such as polyester.

[0009] Furthermore, while titanium oxide is generally used as a white pigment in white water-based inkjet inks, even when titanium oxide whose surface has been treated with an organic compound is used, it is difficult to ensure stability and dispersibility in the case of water-based inks. Furthermore, when printing a fiber structure, it is sometimes difficult to sufficiently conceal the color of the fiber.

[0010] The present invention aims to provide a water-based inkjet ink suitable for inkjet printing of structures made of cotton or synthetic fibers. Another object of the present invention is to provide a method for printing fiber structures by an inkjet method, which is excellent in OD, bleeding suppression, and color development after printing. [Means for solving the problem]

[0011] The present inventors have continued to research chromatic or black water-based inkjet inks suitable for printing fiber structures, particularly structures made of polyester fibers, by an inkjet method. As a result, they have discovered that by combining a pigment with a dispersant having a cationic functional group in a specific ratio, it is possible to obtain a printed product with an excellent OD value after printing an anion-treated structure, and have completed the present invention.

[0012] Furthermore, the present inventors have continued their research into white water-based inkjet inks containing titanium oxide as a white pigment to solve the above-mentioned problems, and as a result have found that it is possible to improve the stability and dispersibility of the white pigment by combining surface-treated titanium oxide as a white pigment with a cationic dispersant having a specific amine value and acid value in a specific ratio. Furthermore, the present inventors have found that it is possible to obtain a printed matter with excellent hiding power (color development) after printing a fiber structure by using such a white water-based inkjet ink, and have completed the present invention.

[0013] Specifically, the present invention provides: A water-based inkjet ink containing at least a pigment, a dispersant, a solvent, and water, The dispersant is a cationic dispersant having an amine value of 10 mgKOH / g or more and the amine value is higher than the acid value, The content of the pigment is 0.01% by mass or more and 30% by mass or less, the value of the dispersant content / the pigment content x 100 is 5 or more and 200 or less, An ink for printing on structures made of cotton or synthetic fibers. This relates to water-based inkjet inks.

[0014] The aqueous inkjet ink of the present invention can improve the dispersibility of the pigment and the OD after printing by combining the pigment with a dispersant having a cationic functional group, and can also suppress bleeding of the print.

[0015] The dispersant is preferably a cationic dispersant having an amine value of 60 mgKOH / g or more and 150 mgKOH / g or less and an acid value of 0 mgKOH / g. Here, "an acid value of 0 mgKOH / g" includes not only an acid value of 0 mgKOH / g but also an acid value below the measurement limit of a conventional acid value measurement method.

[0016] The synthetic fibers are preferably polyester fibers.

[0017] The polyester fiber is preferably anion-treated polyester.

[0018] The pigment is preferably any one of Pigment Yellow 155, Pigment Red 122, Pigment Blue 15:3, or Pigment Black 7 for chromatic or black pigments.

[0019] The pigment is preferably titanium oxide that has been surface-treated with alumina, silica, polyol and / or polysiloxane, in the case of a white pigment.

[0020] In white water-based inkjet inks containing titanium oxide as a white pigment, the stability and dispersibility of titanium oxide particles could not be improved simply by using the surface-treated titanium oxide disclosed in Patent Documents 4 or 5. Furthermore, depending on the type of dispersant used in combination, color development (concealment) may be insufficient when a fiber structure is printed. However, a white water-based inkjet ink containing a specific surface-treated titanium oxide and a specific cationic dispersant in a specific ratio exhibits excellent color development (concealment) even when a fiber structure is printed, and also exhibits excellent stability and dispersibility of titanium oxide particles in the white water-based inkjet ink.

[0021] In the case of a water-based inkjet ink containing a white pigment, it is preferable that (dispersant concentration (mass %) / titanium oxide concentration (mass %))×amine value (mgKOH / g) in the water-based inkjet ink=2.50 to 8.50.

[0022] The present invention also provides A method for printing a fiber structure made of synthetic fibers by an inkjet method, comprising: The method comprises: a step A of anionizing the fiber structure with an anionizing treatment agent; After step A, step B is performed to print the fiber structure by an inkjet method using a water-based inkjet ink; and The water-based inkjet ink comprises Contains at least a pigment, a dispersant, a solvent, and water, The dispersant is a cationic dispersant having an amine value of 10 mgKOH / g or more and the amine value is higher than the acid value, The content of the pigment is 0.01% by mass or more and 30% by mass or less, The value of the dispersant content / pigment content x 100 is 5 or more and 200 or less. Regarding the method.

[0023] The present invention also provides A method for printing a fiber structure made of cotton by an inkjet method, comprising: The method comprises: A step B of printing a fiber structure by an inkjet method using a water-based inkjet ink, The water-based inkjet ink comprises Contains at least a pigment, a dispersant, a solvent, and water, The dispersant is a cationic dispersant having an amine value of 10 mgKOH / g or more and the amine value is higher than the acid value, The content of the pigment is 0.01% by mass or more and 30% by mass or less, The value of the dispersant content / pigment content x 100 is 5 or more and 200 or less. Regarding the method. [Effects of the Invention]

[0024] According to the present invention, it is possible to improve OD and prevent bleeding after printing, particularly when inkjet printing a structure made of anion-treated synthetic fibers in chromatic or black colors.

[0025] Furthermore, the present invention can improve the stability and dispersibility of pigment particles in a white water-based inkjet ink containing surface-treated titanium oxide particles as a white pigment, and can improve the color development after printing, particularly when inkjet printing a structure made of anion-treated synthetic fibers in white. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, an embodiment of the present invention will be described.

[0027] [Pigment] The chromatic or black pigments that can be used in the present invention are not particularly limited, and examples thereof include carbon black, titanium black, CI Nos. 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-169, 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, P R-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-144 , 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, PR-2 Examples of pigments that can be used include, but are not limited to, 38, 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 may be used alone or in combination of two or more.

[0028] The average particle size (average particle size of primary particles) of the chromatic or black pigment in the water-based inkjet ink of the present invention is preferably 10 to 250 nm, from the viewpoint of the sedimentation properties of the chromatic or black pigment particles and the optical density of the printed matter. If the average particle size is less than 10 nm, it becomes difficult to ensure the dispersion stability of the ink. On the other hand, if the particle size exceeds 250 nm, the pigment particles are more likely to sediment.

[0029] The average particle size referred to here is the average value of the major axis and minor axis when 100 or more pigment particles are observed under a transmission electron microscope (the average value of the number of particles measured: major axis (nm) + minor axis (nm) / 2). The same applies to the average particle size of surface-treated titanium oxide described below.

[0030] The white pigment that can be used in the present invention is titanium oxide that has been surface-treated with alumina, silica, and polyol and / or polysiloxane.

[0031] As titanium oxide, either anatase or rutile type may be used, but rutile type is preferred as it has higher hiding power for printed matter.Titanium oxide produced by known production methods such as the chloride method or sulfuric acid method may also be used, but titanium oxide produced by the chloride method is preferred as it has high whiteness.

[0032] The surface of untreated titanium oxide has numerous hydroxyl groups, which are the reason why titanium oxide is hydrophilic. By reacting the hydroxyl groups with organic compounds such as polyol or polysiloxane, the hydroxyl groups are eliminated from the titanium oxide surface, and then covering the titanium oxide with polyol or polysiloxane, the titanium oxide becomes hydrophobic.

[0033] Patent Document 4 states that the organic compound used for the surface treatment of titanium oxide is not particularly limited as long as it can hydrophobize titanium oxide, and gives examples such as polyhydric alcohols, alkanolamines or derivatives thereof, organosilicon compounds, higher fatty acids or metal salts thereof, and organometallic compounds.

[0034] Patent Document 4 also discloses that in addition to surface treatment with an organic compound, titanium oxide is surface treated with an inorganic compound to improve weather resistance and dispersion stability. Examples of the inorganic compound include compounds of silicon, aluminum, zirconium, tin, antimony, and titanium.

[0035] On the other hand, the surface-treated titanium oxide used in the present invention is titanium oxide that has been surface-treated with three types of components: (1) alumina; (2) silica; and (3) organic compounds, such as polyol and / or polysiloxane.

[0036] The average particle size (average particle size of primary particles) of the surface-treated titanium oxide in the aqueous inkjet ink of the present invention is preferably 100 to 400 nm, from the viewpoint of the sedimentation properties of the surface-treated titanium oxide particles and the hiding power of the printed matter. If the average particle size is less than 100 nm, sedimentation of the titanium oxide is unlikely to occur, but the hiding power is reduced, making the ink less practical for use as a white inkjet ink. On the other hand, if the average particle size exceeds 400 nm, the hiding power is sufficient, but sedimentation is likely to occur. The average particle size of the surface-treated titanium oxide is more preferably 150 to 350 nm, and even more preferably 200 to 300 nm.

[0037] [Dispersant] The dispersant used in the present invention is a cationic dispersant having an amine value of 10 mgKOH / g or more, and the amine value is higher than the acid value. The dispersant preferably has an amine value of 10 mgKOH / g or more and an acid value of 0, and more preferably has an amine value of 60 mgKOH / g or more and 150 mgKOH / g or less and an acid value of 0 mgKOH / g. One type of dispersant may be used alone, or two or more types may be used in combination.

[0038] Here, the amine value refers to the amine value per 1 g of dispersant solid content, and is determined by potentiometric titration using a 0.1 N hydrochloric acid aqueous solution, and then converted to the potassium hydroxide equivalent (unit: mgKOH / g). Also, the acid value refers to the acid value per 1 g of dispersant solid content, and can be determined by potentiometric titration in accordance with JIS K 0070 (1992) (unit: mgKOH / g).

[0039] A variety of cationic dispersants having an amine value of 10 mg KOH / g or more and an amine value higher than the acid value are commercially available, such as DISPERBYK-182, 183, 184, 185, 191, 2013, 2050, 2070, 2055, BYKJET-9151, 9152, and 9171 (all manufactured by BYK Japan), EFKA PX-4330, 4350, 4701, 4703, 4733, 4753, and 4780 (all manufactured by BASF), and TEGO Dispers 650 (manufactured by Evonik). These dispersants may be used alone or in combination of two or more.

[0040] In the present invention, the value of (dispersant concentration (mass %) / titanium oxide concentration (mass %))×amine value (mg KOH / g) in a 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 dispersant contained in the water-based inkjet ink as solid content. Furthermore, "titanium oxide concentration (mass %)" refers to the concentration of surface-treated titanium oxide contained in the water-based inkjet ink.

[0041] There are no particular limitations on the solvent that can be used in the present invention, and examples that can be used include monohydric alcohols such as methanol, ethanol, and isopropyl alcohol; polyhydric alcohols; ketones or ketoalcohols such as acetone and diacetone alcohol; and cyclic ethers such as tetrahydrofuran and dioxane.

[0042] The water-based inkjet ink of the present invention may contain additives such as pH adjusters, surfactants, chelating agents, rust inhibitors, antioxidants, UV absorbers, preservatives, antifungal agents, antifoaming agents, etc. The content (concentration) of these additives may be adjusted to a range that allows them to exhibit their functions.

[0043] There are no particular limitations on the pH adjuster that can be used in the present invention, and examples thereof include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; tertiary amines such as triethanolamine, diethanolamine, dimethylethanolamine, and diethylethanolamine; aqueous ammonia, hydrochloric acid, acetic acid, and formic acid.

[0044] There are no particular limitations on the surfactants that can be used in the present invention, and examples thereof include anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, fluorine-based surfactants, and silicone-based surfactants.

[0045] The aqueous inkjet ink of the present invention is obtained by preparing a pigment dispersion (pigment dispersion), adding a solvent, additives, etc. to the pigment dispersion, and mixing the mixture. The pigment dispersion can be produced by mixing the pigment and dispersion, etc., and dispersing the mixture using a sand mill (bead mill), a roll mill, a ball mill, a paint shaker, an ultrasonic disperser, a high-pressure emulsifier, etc.

[0046] The aqueous inkjet ink of the present invention is obtained by preparing a pigment dispersion (pigment dispersion), adding a solvent, additives, etc. to the pigment dispersion, and mixing the mixture. The pigment dispersion can be produced by mixing the pigment and dispersion, etc., and dispersing the mixture using a sand mill (bead mill), a roll mill, a ball mill, a paint shaker, an ultrasonic disperser, a high-pressure emulsifier, etc.

[0047] As an example, the case of dispersion treatment using a sand mill will be described. First, the pigment, dispersant, and beads serving as the dispersion medium are charged into the sand mill. As the beads, glass beads, zirconia beads, etc. with a particle diameter of 0.01 to 1 mm can be used. The amount of beads used is preferably 2 to 6 weights per weight of ink. Then, the sand mill is operated to perform dispersion treatment. The dispersion treatment conditions are preferably approximately 1000 to 2000 rpm for 1 to 20 hours. After dispersion treatment, the beads are removed by filtration or the like to obtain a pigment dispersion liquid.

[0048] The pigment concentration (% by mass) in the water-based inkjet ink of the present invention is preferably 0.01% to 30% by mass, more preferably 0.01% to 20% by mass, and even more preferably 1% to 15% by mass, for any of the chromatic, black, and white pigments. By keeping the concentration within this range, sufficient color development (hiding ability) can be obtained, and the ink also tends to have excellent storage stability.

[0049] The pH of the aqueous inkjet ink is preferably from 3 to 11, and more preferably from 4 to 10. When the pH is within this range, the ink has excellent storage stability and damage to the ejection device or fiber structure can be suppressed.

[0050] <Production of Water-Based Inkjet Inks 1: Chromatic or Black> (Example 1 / Cyan ink) A sand mill was charged with 15.0 parts by weight of CYANINE BLUE KRO (PB-15:3, manufactured by Sanyo Pigment Co., Ltd.) as a cyan pigment, 11.5 parts by weight of Dispersant C (DISPERBYK-185, manufactured by BYK Japan; amine value = 17 mg KOH / g, active ingredient 52%) as a dispersant, 73.5 parts by weight of ion-exchanged water, and 400 parts by weight of 0.5 mm diameter zirconia beads. The mixture was then dispersed at 1,500 rpm for 3 hours. The zirconia beads were then removed to obtain a pigment dispersion. The particle sizes of the pigment and dispersant were adjusted to approximately 100-110 nm.

[0051] To this pigment dispersion, as shown in Table 1, BYK-348 (polyether-modified siloxane manufactured by BYK Japan) as a surfactant, formic acid or triethanolamine as a pH adjuster, and 1,2-hexanediol, glycerin, and ion-exchanged water as solvents were mixed to produce a cyan ink with a pH of 9. The water-based inkjet inks of Examples 1 to 11 and Comparative Examples 1 to 10 were prepared in a total amount of 100.0 parts by weight.

[0052] [Table 1]

[0053] (Example 2 / Magenta ink) A magenta ink was produced in the same manner as in Example 1, except that FASTOGEN SUPER MAGENTA RG (PR-122 manufactured by DIC Corporation) was used as the magenta pigment.

[0054] (Example 3 / Yellow Ink) A yellow ink was produced in the same manner as in Example 1, except that Inkjet Yellow 4GC (PY-155 manufactured by Clariant) was used as the yellow pigment.

[0055] (Example 4 / Black ink) A black ink was produced in the same manner as in Example 1, except that NIPex 160IQ (carbon black manufactured by Orion Engineered Carbons) was used as the black pigment.

[0056] (Example 5 / Cyan ink) A cyan ink was prepared in the same manner as in Example 1, except that 6.0 parts by weight of Dispersant D (EFKA PX4701 (BASF, amine value = 40 mgKOH / g, active ingredient 100%)) was used as the dispersant, and 79.0 parts by weight of ion-exchanged water was used.

[0057] (Example 6 / Cyan Ink) A cyan ink was prepared in the same manner as in Example 1, except that 6.0 parts by weight of Dispersant E (BYKJET-9151 (manufactured by BYK Japan; amine value = 18 mgKOH / g, acid value = 8 mgKOH / g, active ingredient 100%) was used as the dispersant, and 79.0 parts by weight of ion-exchanged water was used.

[0058] (Example 7 / Cyan ink) A cyan ink was prepared in the same manner as in Example 1, except that 6.0 parts by weight of Dispersant I (BYKJET-9152 (manufactured by BYK Japan; amine value = 19 mg KOH / g, acid value = 6 mg KOH / g, active ingredient 100%) was used as the dispersant, and 79.0 parts by weight of ion-exchanged water was used.

[0059] (Example 8 / Cyan ink) A cyan ink was prepared in the same manner as in Example 1, except that the amount of Dispersant C was 8.7 parts by weight and the amount of ion-exchanged water was 76.3 parts by weight.

[0060] (Example 9 / Cyan Ink) A cyan ink was prepared in the same manner as in Example 1, except that the amount of Dispersant C was 17.3 parts by weight and the amount of ion-exchanged water was 67.7 parts by weight.

[0061] (Example 10 / Cyan ink) A cyan ink was produced in the same manner as in Example 1, except that 37.5 parts by weight of Dispersant A (amine value 67 mgKOH / g, solid content 20%) described below was used as the dispersant, and 47.5 parts by weight of ion-exchanged water was used.

[0062] (Example 11 / Cyan ink) A cyan ink was produced in the same manner as in Example 1, except that 37.5 parts by weight of Dispersant B (amine value 135 mgKOH / g, solid content 20%) described below was used as the dispersant, and 47.5 parts by weight of ion-exchanged water was used.

[0063] [Method of manufacturing dispersant A] A resin with a monomer composition ratio of benzyl methacrylate / dimethylaminoethyl methacrylate = 80 / 20 (mass ratio) and an amine value of 67 mgKOH / g was prepared. Formic acid and ion-exchanged water were added to this resin to dissolve it, and the solid content was adjusted to 20%, to obtain Dispersant A.

[0064] [Method of manufacturing dispersant B] A resin with a monomer composition ratio of benzyl methacrylate / dimethylaminoethyl methacrylate = 60 / 40 (mass ratio) and an amine value of 135 mgKOH / g was prepared. Formic acid and ion-exchanged water were added to this resin to dissolve it, and the solid content was adjusted to 20%, to obtain Dispersant B.

[0065] (Comparative Example 1 / Cyan Ink) A cyan ink was prepared in the same manner as in Example 1, except that 15.0 parts by weight of Dispersant F (DISPERBYK-190 (manufactured by BYK Japan; acid value = 10 mg KOH / g, active ingredient 40%)) was used as the dispersant, and 70.0 parts by weight of ion-exchanged water was used.

[0066] (Comparative Example 2 / Cyan Ink) A cyan ink was prepared in the same manner as in Example 1, except that 20.0 parts by weight of dispersant J (Joncryl 63J (BASF; acid value = 213 mg KOH / g, active ingredient 30%)) and 65.0 parts by weight of ion-exchanged water were used as the dispersant.

[0067] (Comparative Example 3 / Magenta Ink) A magenta ink was produced in the same manner as in Example 2, except that the dispersant used was 15.0 parts by weight of Dispersant F and 70.0 parts by weight of ion-exchanged water.

[0068] (Comparative Example 4 / Magenta Ink) A magenta ink was produced in the same manner as in Example 2, except that the dispersant used was 20.0 parts by weight of Dispersant J and 65.0 parts by weight of ion-exchanged water.

[0069] (Comparative Example 5 / Yellow Ink) A yellow ink was produced in the same manner as in Example 3, except that the dispersants used were 15.0 parts by weight of Dispersant F and 70.0 parts by weight of ion-exchanged water.

[0070] (Comparative Example 6 / Yellow Ink) A yellow ink was produced in the same manner as in Example 3, except that 20.0 parts by weight of Dispersant J (as a dispersant) and 65.0 parts by weight of ion-exchanged water were used.

[0071] (Comparative Example 7 / Black Ink) A black ink was produced in the same manner as in Example 4, except that the dispersant used was Dispersant F (15.0 parts by weight) and ion-exchanged water (70.0 parts by weight).

[0072] (Comparative Example 8 / Black Ink) A black ink was produced in the same manner as in Example 4, except that the dispersant used was 20.0 parts by weight of Dispersant J and 65.0 parts by weight of ion-exchanged water.

[0073] (Comparative Example 9 / Cyan Ink) A cyan ink was prepared in the same manner as in Example 1, except that 7.5 parts by weight of Dispersant G (DISPERBYK-180 (manufactured by BYK Japan, amine value 94 mgKOH / g, acid value 94 mgKOH / g, active ingredient 100%) was used as the dispersant, and 77.5 parts by weight of ion-exchanged water was used.

[0074] (Comparative Example 10 / Cyan Ink) A cyan ink was prepared in the same manner as in Example 1, except that 7.5 parts by weight of Dispersant H (DISPERBYK-191 (manufactured by BYK Japan, amine value 20 mgKOH / g, acid value 30 mgKOH / g, active ingredient 100%) was used as the dispersant, and 77.5 parts by weight of ion-exchanged water was used.

[0075] <Fiber structure> The following three types of samples were used as the fiber structures to be printed. Cotton structure: 100% cotton fabric (Irozome Co., Ltd. cotton broadcloth, unspun) Polyester structure (untreated polyester structure): 100% polyester fabric (Toray Amina) Anion-treated polyester structure (anion-treated polyester structure): A structure in which the same structure as the polyester structure is treated with an anionizing agent

[0076] <Anionization Treatment Method / Step A> A 6 g / L solution of a cationic polymerization agent (cationic polymer compound / Sanyo Dye Co., Ltd., cationizing agent CT F1101) was applied to the polyester structure by 1DIP / 1NIP and then dried at 130°C for 3 minutes. Next, a 60 g / L solution of an anionic polymerization agent was applied by 1DIP / 1NIP and then dried at 130°C for 3 minutes to obtain an anionized polyester structure.

[0077] Here, "anionization treatment" in the present invention means attaching an anionic polymerization agent to a structure made of synthetic fibers. The anionic polymerization 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, polybutylene naphthalate, etc., and refer to those emulsified using an activator.

[0078] It is also preferable to carry out a cationization treatment with a cationic polymerization agent prior to such treatment. As the cationic polymerization agent, a known polymer (polymer or prepolymer) containing a tertiary amino group, a quaternary ammonium group, or both in the molecule can be used, and further, a cationic compound generally used as a cationization agent can also be used.

[0079] Examples of tertiary amino group-containing polymers include: (a) polymers of alkylaminoalkyl(meth)acrylamides, such as polymers of dimethyl or diethylaminoethyl(meth)acrylamide, dimethyl or diethylaminopropyl(meth)acrylamide, etc.; (b) polymers of dialkylaminoalkyl(meth)acrylates, such as polymers of dimethyl or diethylaminoethyl(meth)acrylate, dimethyl or diethylaminopropyl(meth)acrylate, etc.; (c) acrylamide-styrene copolymers; and (d) urethane polymers containing tertiary amino groups.

[0080] Examples of the quaternary ammonium group-containing polymer include: (e) polymers of (meth)acryloyloxyalkyltrialkylammonium salts, such as polymers of 2-(meth)acryloyloxyethyltrimethylammonium chloride and 3-(meth)acryloyloxy-2-hydroxypropyltrimethylammonium chloride; (f) polymers of (meth)acrylamidoalkyltrialkylammonium salts, such as polymers of 3-(meth)acrylamidopropyltrimethylammonium chloride and 3-(meth)acryloylamino-2-hydroxypropyltrimethylammonium chloride; (g) polymers of 2-(meth)acryloyloxyalkylbenzylammonium salts, such as polymers of 2-(meth)acryloyloxyethylbenzylammonium chloride and 2- (h) copolymers of acrylamidopropyl dimethylbenzyl chloride and N,N-dimethylacrylamide, and copolymers of N-methyl-N-benzylallylamine salt and N-methyl-N-hydroxyethylaminopropyl acrylamide; (i) polymers of dimethyl or diethyl diallyl ammonium chloride, β-vinyloxyethyl trialkyl ammonium salt, vinyl benzyl ammonium salt, and the like;

[0081] Furthermore, as the cationic compound, (j) a quaternary ammonium group-containing compound 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-epoxypropyl-trimethylammonium chloride, etc. can be used. Among them, polydialkylamino (meth)acrylate, polydimethyldiallylammonium chloride, and a urethane polymer containing a tertiary amino group are preferable.

[0082] Note that the anionization treatment in the present invention is not limited to the treatment described in Step A described later.

[0083] <Printing of Fiber Structure / Step B> Three types of fiber structures were used as printing targets and printed with an inkjet printer with a resolution of 600 dpi using the prepared aqueous inkjet ink to form a solid image.

[0084] <OD Value Measurement Method> The optical density of the surface of the obtained solid image was measured with a reflection densitometer GretagMacbeth RD-19 (manufactured by Sakata Inx Engineering Co., Ltd.).

[0085] <Bleeding> For the obtained solid image, the maximum distance at which the ink bled out was measured using a ruler.

[0086] The OD values, OD evaluation, and bleeding evaluation results for the cyan, magenta, yellow, and black water-based inkjet inks are shown in Tables 2 to 5, respectively. In Tables 2 to 5, the OD evaluation for yellow, cyan, and black is as follows: OD values ​​of 1.15 or more are evaluated as "Excellent", 1.10 or more are evaluated as "Good", 1.05 or more but less than 1.10 are evaluated as "Average", and less than 1.05 is evaluated as "Poor". For magenta, OD values ​​of 1.00 or more are evaluated as "Good", and less than 1.00 are evaluated as "Average". Furthermore, bleeding evaluation for all four colors is as follows: OD values ​​of less than 1 mm are evaluated as "Good", 1 mm or more but less than 2 mm are evaluated as "Average", and 2 mm or more are evaluated as "Poor". The same evaluation is applied to Tables 6 to 8, which will be described later.

[0087] [Table 2]

[0088] [Table 3]

[0089] [Table 4]

[0090] [Table 5]

[0091] For the cotton structure, the inks using dispersant C (Examples 1 to 4) of all colors were evaluated as "good" in terms of OD and bleeding. On the other hand, when dispersant F (Comparative Examples 1, 3, 5, and 7) or dispersant J (Comparative Examples 2, 4, 6, and 8) were used as the dispersant, the OD and bleeding evaluations were evaluated as "poor," and it was determined that they lacked practicality.

[0092] For the structures made with untreated polyester, the OD evaluation or bleeding evaluation was "×" for all colors and all dispersants, and it was determined that they lacked practicality. However, for the structures made with anion-treated polyester (shown as "treated polyester" in Tables 2 to 5) in which the same structures were anion-treated, the inks (Examples 1 to 4) using dispersant C for all colors were evaluated as "○" for OD and bleeding.

[0093] The OD value, OD evaluation, and bleeding evaluation results for the cyan water-based inkjet of Examples 5 to 7 are shown in Table 6. In Examples 5 to 7, which used Dispersant D, Dispersant E, and Dispersant I as the dispersants used in the pigment dispersion liquid, the same test results as in Example 1 were obtained.

[0094] [Table 6]

[0095] The OD value, OD evaluation, and bleeding evaluation results for the cyan water-based inkjet prints of Examples 1, 8, and 9 are shown in Table 7. It was confirmed that when the value of dispersant content (D) / pigment content (P)×100 was in the range of 30 to 60, the D evaluation and bleeding evaluation were "Good" for cotton or anion-treated polyester.

[0096] [Table 7]

[0097] The OD values, OD evaluation, and bleeding evaluation results for the cyan water-based inkjet of Examples 10 to 11 and Comparative Examples 9 and 10 are shown in Table 8. Examples 10 to 11, which used Dispersant A and Dispersant B as dispersants in the pigment dispersion, were rated "◎" for OD and "○" for bleeding, making them the most excellent of the Examples.

[0098] [Table 8]

[0099] As described above, it was confirmed that the water-based inkjet ink of the present invention, which contains a pigment and a specific cationic dispersant, is more suitable for printing on fiber structures made of cotton or anion-treated polyester fibers than water-based inkjet inks containing the same pigment and other dispersants.

[0100] Tables 2 to 8 confirm that, in the case of aqueous inkjet inks containing chromatic or black pigments, the preferred dispersant is a "cationic dispersant having an amine value of 10 mgKOH / g or more and which is higher than its acid value," and that "cationic dispersants having an amine value of 60 mgKOH / g or more and 150 mgKOH / g or less and an acid value of 0 mgKOH / g," such as Dispersant A and Dispersant B, are more preferred.

[0101] <Water-based inkjet ink production 2: White> Example 12 40.0 parts by weight of Typeque PF-728 (manufactured by Ishihara Sangyo Kaisha, Ltd., alumina / silica / polysiloxane treatment) as titanium oxide, 20.0 parts by weight of Dispersant A as dispersant, 40.0 parts by weight of ion-exchanged water, and 400 parts by weight of 0.5 mm diameter zirconia beads were charged into a sand mill and subjected to dispersion treatment at 1,500 rpm for 2 hours. The zirconia beads were then removed to obtain a titanium oxide dispersion.

[0102] The white ink of Example 12 was produced by mixing this titanium oxide dispersion, BYK-348 (a polyether-modified siloxane manufactured by BYK Japan) as a surfactant, 1,2-hexanediol as a solvent, glycerin, and ion-exchanged water in the amounts shown in Table 9. The water-based inkjet inks of Examples 12 to 25 and Comparative Examples 11 to 27 were prepared in a total amount of 100.0 parts by weight.

[0103] [Table 9]

[0104] Example 13 A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 10.0 parts by weight of Dispersant B was used as the dispersant and 50.0 parts by weight of ion-exchanged water was used. Thereafter, a white ink of Example 13 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0105] Example 14 A titanium oxide dispersion was prepared in the same manner as in Example 1, except that 15.3 parts by weight of Dispersant C (DISPERBYK-185 manufactured by BYK Japan, amine value 17 mgKOH / g, solids content 52%) was used as the dispersant and 44.7 parts by weight of ion-exchanged water was used. Thereafter, a white ink of Example 3 was prepared in the same manner as in Example 1, using the blending amounts shown in Table 9.

[0106] Example 15 A titanium oxide dispersion was prepared in the same manner as in Example 1, except that 6.0 parts by weight of Dispersant D was used as the dispersant and 54.0 parts by weight of ion-exchanged water was used. Thereafter, a white ink of Example 15 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0107] Example 16 A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 6.0 parts by weight of Dispersant E was used as the dispersant and 54.0 parts by weight of ion-exchanged water was used. Thereafter, a white ink of Example 16 was prepared in the same manner as in Example 1, using the blending amounts shown in Table 9.

[0108] Example 17 A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 40.0 parts by weight of Typeque PF-740 (manufactured by Ishihara Sangyo Kaisha, Ltd., alumina / zirconia / silica / polysiloxane treatment) was used. Thereafter, a white ink of Example 17 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0109] Example 18 A titanium oxide dispersion was prepared in the same manner as in Example 15, except that the amount of Typeque PF-740 was 40.0 parts by weight. Thereafter, a white ink of Example 18 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0110] Example 19 A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 40.0 parts by weight of Typeque CR-63 (alumina / silica / polyol / polysiloxane treated, manufactured by Ishihara Sangyo Kaisha, Ltd.) was used as the titanium oxide. Thereafter, a white ink of Example 19 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0111] Example 20 A titanium oxide dispersion was prepared in the same manner as in Example 15, except that 40.0 parts by weight of Typeque CR-63 was used as the titanium oxide. Thereafter, a white ink of Example 20 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0112] Example 21 A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 40.0 parts by weight of Typeque PF-671 (manufactured by Ishihara Sangyo Kaisha, Ltd., alumina / silica / polyol treatment) was used as the titanium oxide. Thereafter, a white ink of Example 21 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0113] Example 22 A titanium oxide dispersion was prepared in the same manner as in Example 15, except that 40.0 parts by weight of Typeque PF-671 was used as the titanium oxide. Thereafter, a white ink of Example 22 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0114] Example 23 A titanium oxide dispersion was prepared in the same manner as in Example 12, except that Dispersant A was used in an amount of 10.0 parts by weight and ion-exchanged water in an amount of 50.0 parts by weight. Thereafter, a white ink of Example 23 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0115] Example 24 A titanium oxide dispersion was prepared in the same manner as in Example 13, except that the amount of dispersant B was 6.0 parts by weight and the amount of ion-exchanged water was 54.0 parts by weight. Thereafter, a white ink of Example 13 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0116] Example 25 A titanium oxide dispersion was prepared in the same manner as in Example 15, except that Dispersant D was used at 8.0 parts by weight and ion-exchanged water at 52.0 parts by weight. Thereafter, a white ink of Example 25 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0117] (Comparative Example 11) A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 40.0 parts by weight of Typeque PF-726 (manufactured by Ishihara Sangyo Kaisha, Ltd., alumina / silica treated) was used as the titanium oxide. Thereafter, a white ink of Comparative Example 11 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0118] (Comparative Example 12) A titanium oxide dispersion was prepared in the same manner as in Example 13, except that 40.0 parts by weight of Typeque PF-726 was used as the titanium oxide. Thereafter, a white ink of Comparative Example 12 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0119] (Comparative Example 13) A titanium oxide dispersion was prepared in the same manner as in Example 14, except that 40.0 parts by weight of Typeque PF-726 was used as the titanium oxide. Thereafter, a white ink of Comparative Example 13 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0120] (Comparative Example 14) A titanium oxide dispersion was prepared in the same manner as in Example 15, except that 40.0 parts by weight of Typeque PF-726 was used as the titanium oxide. Thereafter, a white ink of Comparative Example 14 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0121] (Comparative Example 15) A titanium oxide dispersion was prepared in the same manner as in Example 16, except that 40.0 parts by weight of Typeque PF-726 was used as the titanium oxide. Thereafter, a white ink of Comparative Example 15 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0122] (Comparative Example 16) A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 40.0 parts by weight of Typeque CR-50 (alumina-treated, manufactured by Ishihara Sangyo Kaisha, Ltd.) was used as the titanium oxide. Thereafter, a white ink of Comparative Example 16 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0123] (Comparative Example 17) A titanium oxide dispersion was prepared in the same manner as in Example 15, except that 40.0 parts by weight of Typeque CR-50 was used as the titanium oxide. Then, an ink of Comparative Example 17 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0124] (Comparative Example 18) A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 40.0 parts by weight of Typeque CR-50-2 (manufactured by Ishihara Sangyo Kaisha, Ltd., alumina / polyol treatment) was used as the titanium oxide. Thereafter, a white ink of Comparative Example 18 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0125] (Comparative Example 19) A titanium oxide dispersion was prepared in the same manner as in Example 15, except that 40.0 parts by weight of Typeque CR-50-2 was used as the titanium oxide. Thereafter, a white ink of Comparative Example 19 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0126] (Comparative Example 20) A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 10.0 parts by weight of Dispersant F was used as the dispersant and 50.0 parts by weight of ion-exchanged water was used. Thereafter, a white ink of Comparative Example 20 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0127] (Comparative Example 21) A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 3.2 parts by weight of Dispersant G was used as the dispersant and 56.8 parts by weight of ion-exchanged water was used. Thereafter, a white ink of Comparative Example 21 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0128] (Comparative Example 22) A titanium oxide dispersion was prepared in the same manner as in Example 12, except that 6.0 parts by weight of Dispersant H was used as the dispersant and 54.0 parts by weight of ion-exchanged water was used. Thereafter, a white ink of Comparative Example 22 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0129] (Comparative Example 23) A titanium oxide dispersion was prepared in the same manner as in Example 12, except that Dispersant A was used at 6.0 parts by weight and ion-exchanged water at 54.0 parts by weight. Thereafter, a white ink of Comparative Example 23 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0130] (Comparative Example 24) A titanium oxide dispersion was prepared in the same manner as in Example 1, except that the amounts of Dispersant A and ion-exchanged water were 30.0 parts by weight and 30.0 parts by weight, respectively. Thereafter, a white ink of Comparative Example 14 was prepared in the same manner as in Example 1, using the blending amounts shown in Table 1.

[0131] (Comparative Example 25) A titanium oxide dispersion was prepared in the same manner as in Example 13, except that Dispersant B was used in an amount of 16.0 parts by weight and ion-exchanged water in an amount of 44.0 parts by weight. Thereafter, a white ink of Comparative Example 25 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0132] (Comparative Example 26) A titanium oxide dispersion was prepared in the same manner as in Example 15, except that Dispersant D was used at 2.0 parts by weight and ion-exchanged water at 58.0 parts by weight. Thereafter, a white ink of Comparative Example 26 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0133] (Comparative Example 27) A titanium oxide dispersion was prepared in the same manner as in Example 15, except that Dispersant D was used in an amount of 10.0 parts by weight and ion-exchanged water in an amount of 50.0 parts by weight. Thereafter, a white ink of Comparative Example 27 was prepared in the same manner as in Example 12, using the blending amounts shown in Table 9.

[0134] <Stability test> 10 g of the white inks of Examples 12 to 25 and Comparative Examples 10 to 27 were placed in a sealed container and allowed to stand for one week in a thermostatic chamber at 60°C. After cooling to room temperature, the average particle size (average particle size of titanium oxide particles, which is the pigment) and viscosity in the white ink were measured using a light scattering photometer and an E-type viscometer. The average particle size (average particle size of titanium oxide particles, which is the pigment) and viscosity were also measured before the start of the stability test. The average particle size or viscosity before the start of the stability test was designated (A) and the average particle size or viscosity after the stability test was designated (B), and the rate of increase in the measured value was calculated using the following formula. Growth rate (%) = (BA) / A × 100

[0135] The stability of each white ink was evaluated based on the calculated increase rate according to the following evaluation criteria, with "B" or better being a practical level. ○: The increase in both average particle size and viscosity is less than 10% △: The increase rate of either the average particle size or viscosity is 10% or more ×: The increase rate of both the average particle size and viscosity is 10% or more

[0136] <Sedimentation test> 10 g of the white inks of Examples 12 to 25 and Comparative Examples 10 to 27 were placed in a glass container and allowed to stand for 3 days in a thermostatic chamber at 25°C. The sedimentation properties of each white ink were then evaluated based on the following criteria. A rating of "good" indicates a level suitable for practical use. ○: No sediment was observed at the bottom of the glass container. ×: Sediment was observed at the bottom of the glass container.

[0137] <Anionization Treatment Method / Step A> An anion-treated polyester structure was obtained by step A of the above-mentioned aqueous inkjet ink production 1.

[0138] <Printing of fiber structures / Process B> The white inks of Examples 12 to 25 and Comparative Examples 10 to 27 were used to perform solid printing on the following substrates using a printer with a resolution of 600 dpi. Base material 1: Black cotton cloth (Kurabo H.444) Substrate 2: The above-mentioned anion-treated black polyester fabric

[0139] <Opacity test> The OD values ​​of the image surfaces obtained for the substrates 1 and 2 were measured using a reflection densitometer (GretagMacbeth RD-19, Sakata Inx Engineering Co., Ltd.), and the hiding power was calculated based on the following formula. Hiding power (%) = (1 - OD of printed item / OD of black cotton cloth before printing) x 100

[0140] Thereafter, the hiding power of each white ink was evaluated based on the following evaluation criteria, with a rating of "B" or higher being at a practical level. ◎: Hiding power 70% or more ○: Hiding power is 50% or more but less than 70% △: Hiding power is 30% or more but less than 50% ×: Hiding power less than 30%

[0141] Table 10 shows the evaluation results of the white inks of Examples 11 to 25, including (1) the contents of the white pigment, dispersant, and ion-exchanged water in the pigment dispersion; (2) the value of (dispersant concentration (mass%) / titanium oxide concentration (mass%))×amine value (mgKOH / g); and (3) the stability test, sedimentation test, and opacity test. Table 11 shows the evaluation results of the white inks of Comparative Examples 10 to 27, including (1) the contents of the white pigment, dispersant, and ion-exchanged water; (2) the value of (dispersant concentration (mass%) / titanium oxide concentration (mass%))×amine value; and (3) the stability test, sedimentation test, and opacity test.

[0142] [Table 10]

[0143] [Table 11]

[0144] As can be seen from Table 10, the white inks of Examples 12 to 25 were "practical" for all evaluation items. All evaluation items except for Example 16 were rated "○" or better. Furthermore, Examples 12, 13, 17, 19, 21, 23, and 24 were rated "○" for stability and sedimentation, and were particularly excellent in hiding power, with a rating of "◎." On the other hand, as can be seen from Table 11, the white inks of Comparative Examples 10 to 27 were rated "×" for any of the evaluation items, and were therefore deemed unpractical.

[0145] In the case of the white ink of Example 12, the dispersant content in 25.0 parts by weight of titanium oxide dispersion is 20.0 × (25 / 100) × 0.2 parts by weight, and the solid content of the dispersant is 20.0 × (25 / 100) × 0.2 parts by weight. The titanium oxide content in 25.0 parts by weight of titanium oxide dispersion is 40.0 × (25 / 100) × 0.2 parts by weight. Since the total amount of white ink is 100 parts by weight, the formula for the white ink (aqueous inkjet ink) is (dispersant concentration (mass%) / titanium oxide concentration (mass%)) × amine value (mg KOH / g) is 20.0 × (25 / 100) × 0.2 (%) / 40.0 × (25 / 100) (%) × 67 = 6.70. Similarly, the formula for (dispersant concentration (mass%) / titanium oxide concentration (mass%)) × amine value (mg KOH / g) is calculated for the white inks of the other Examples and Comparative Examples.

[0146] Tables 10 and 11 confirm that white inks with excellent stability, sedimentation resistance, and hiding power satisfy the following conditions: (i) the white pigment contains titanium dioxide that has been surface-treated with alumina, silica, and a polyol and / or polysiloxane; (ii) the cationic dispersant has an amine value of 10 mgKOH / g or more, and the amine value is greater than the acid value; and (iii) the value of (dispersant concentration (mass%) / titanium oxide concentration (mass%)) × amine value (mgKOH / g) is 2.50 to 8.50. Furthermore, it was considered that the value of (dispersant concentration (mass%) / titanium oxide concentration (mass%)) × amine value (mgKOH / g) is more preferably 3.20 to 8.20, and even more preferably 3.20 to 7.00. It was considered that the cationic dispersant more preferably has an amine value of 60 mgKOH / g or more and 150 mgKOH / g or less, and an acid value of 0 mgKOH / g.

[0147] As described above, it has been confirmed that the aqueous inkjet ink of the present invention, which contains a pigment and a specific cationic dispersant, is more suitable for printing on fiber structures made of cotton or anion-treated polyester fibers than aqueous inkjet inks containing the same pigment and other dispersants. Furthermore, when the aqueous inkjet ink of the present invention contains surface-treated titanium oxide as a white pigment, it has excellent pigment particle stability and dispersibility. Furthermore, even when printing on fiber structures, it is possible to sufficiently conceal the color of the fibers. [Industrial Applicability]

[0148] The water-based ink-jet ink and the method for printing a fiber structure by an ink-jet method of the present invention are useful in the field of printing.

Claims

1. A water-based inkjet ink containing at least a pigment, a dispersant, a solvent, and water, The dispersant is a cationic dispersant having an amine value of 10 mgKOH / g or more and the amine value is higher than the acid value, The content of the pigment is 0.01% by mass or more and 30% by mass or less, the value of the dispersant content / the pigment content x 100 is 5 or more and 200 or less, An ink for printing on structures made of cotton or synthetic fibers. Water-based inkjet ink.

2. The dispersant is a cationic dispersant having an amine value of 60 mgKOH / g or more and 150 mgKOH / g or less and an acid value of 0 mgKOH / g. The water-based inkjet ink of claim 1.

3. The water-based inkjet ink according to claim 1 or 2, wherein the synthetic fibers are polyester fibers.

4. The water-based ink-jet ink of claim 3 , wherein the polyester fiber is anionically treated polyester.

5. 5. The water-based ink-jet ink according to claim 1, wherein the pigment is any one of Pigment Yellow 155, Pigment Red 122, Pigment Blue 15:3, and Pigment Black 7.

6. 5. The water-based ink-jet ink according to claim 1, wherein the pigment is titanium oxide that has been surface-treated with alumina, silica, and a polyol and / or polysiloxane.

7. 7. The water-based ink-jet ink according to claim 6, wherein (dispersant concentration (mass %) / titanium oxide concentration (mass %))×amine value (mgKOH / g) in the water-based ink-jet ink is 2.50 to 8.

50.

8. A method for printing a fiber structure made of synthetic fibers by an inkjet method, comprising: The method comprises: a step A of anionizing the fiber structure with an anionizing treatment agent; After the step A, a step B is performed in which the fiber structure is printed by an inkjet method using a water-based inkjet ink; and The water-based inkjet ink comprises Contains at least a pigment, a dispersant, a solvent, and water, The dispersant is a cationic dispersant having an amine value of 10 mgKOH / g or more and the amine value is higher than the acid value, The content of the pigment is 0.01% by mass or more and 30% by mass or less, the value of the dispersant content / the pigment content x 100 is 5 or more and 200 or less; method.

9. A method for printing a fiber structure made of cotton by an inkjet method, comprising: The method comprises: A step B of printing a fiber structure by an inkjet method using a water-based inkjet ink, The water-based inkjet ink comprises Contains at least a pigment, a dispersant, a solvent, and water, The dispersant is a cationic dispersant having an amine value of 10 mgKOH / g or more and the amine value is higher than the acid value, The content of the pigment is 0.01% by mass or more and 30% by mass or less, the value of the dispersant content / the pigment content x 100 is 5 or more and 200 or less; method.

10. The dispersant is a cationic dispersant having an amine value of 60 mgKOH / g or more and 150 mgKOH / g or less and an acid value of 0 mgKOH / g.

10. The method according to claim 8 or 9.

11. 11. The method of claim 8 or 10, wherein the synthetic fibers are polyester fibers.

12. 12. The method of claim 8, 10 or 11, wherein the anionic treating agent is a polyester emulsion.

13. 13. The method of claim 8, wherein the pigment is any of Pigment Yellow 155, Pigment Red 122, Pigment Blue 15:3, or Pigment Black 7.

14. 13. The method according to any one of claims 8 to 12, wherein the pigment is titanium oxide surface-treated with alumina, silica, and polyol and / or polysiloxane.

15. 15. The water-based ink-jet ink according to claim 14, wherein (dispersant concentration (% by mass) / titanium oxide concentration (% by mass))×amine value (mgKOH / g)=2.50 to 8.50.

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