CN116133865A - Aqueous inkjet ink, method of printing fiber structure by inkjet method - Google Patents

Abstract

An object of the present invention is to provide an aqueous 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 of printing a fiber structure by an inkjet method that is excellent in optical density (OD) after printing, bleed suppression, and color rendering. The water-based inkjet ink of the present invention (1) contains at least pigment, dispersant, solvent and water; (2) the dispersant is a cationic dispersant whose amine value is more than 10mgKOH/g, and the amine value is higher than the acid value; (3) The pigment content is not less than 0.01% by mass and not more than 30% by mass; (4) The value of dispersant content/pigment content x 100 is 5 to 200; (5) For printing on structures made of cotton or synthetic fibers ink.

Description

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

Technical Field

The present invention relates to an aqueous inkjet ink for a cotton material or a synthetic fiber structure. In addition, the present invention relates to a method for printing a fiber structure by anionizing the fiber structure using an inkjet method.

Background Art

There are several methods for recording images on recording media such as paper, such as electrophotography, sublimation, melt thermal transfer, and inkjet. Among them, inkjet printing equipment is cheap and does not require plate making during printing. In addition, the image is formed directly on the recording medium by simply ejecting the ink composition at the necessary image portion, so the ink composition can be used efficiently, and the running cost is low, especially in small-batch production.

Inkjet inks include dye inks and pigment inks. When using pigment inks, the color tone and sharpness are generally inferior to those when using dye inks, but the pigment itself has excellent light resistance and water resistance. In addition, inkjet dyeing using pigment inks has the advantage of not requiring complicated post-processing of fabrics compared to using dye inks. Therefore, inkjet printing methods using pigment inks are currently attracting attention as printing methods for fiber structures such as clothing.

As inkjet printing methods using pigment inks, there are known methods of dyeing a fabric 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 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); a method of dyeing a fabric to which a hydrophobic low molecular weight compound and a cationic resin are applied with a pigment ink and heat-treated to form a thin film (Patent Document 3), etc. The purpose of these methods is to improve the sharpness, water resistance, abrasion resistance, etc. of the printed image.

Patent document 4 discloses an aqueous pigment dispersion having low viscosity and excellent storage stability and an aqueous inkjet ink having excellent hiding power, using titanium oxide as a pigment. The aqueous pigment dispersion of patent document 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).

Patent Document 5 discloses a non-aqueous white ink for active energy ray curable inkjet comprising titanium oxide, a pigment dispersant and a polymerizable compound. In Patent Document 5, as titanium oxide, titanium oxide surface-treated with silicon dioxide is preferably used.

Prior art literature:

Patent literature:

Patent document 1: Japanese Patent Application Laid-Open 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

Problems to be solved by the invention:

However, when using water-based inkjet ink and printing on fiber structures (fibrous structures) such as T-shirts, fabrics or flags by the inkjet method, there is a problem of poor OD (optical density) compared to the case of printing on printing paper even if the same water-based inkjet ink is used. This problem is particularly prominent when the structure composed of synthetic fibers such as polyester is the printing object.

In addition, white water-based inkjet inks generally use titanium oxide as a white pigment, but even if titanium oxide is surface-treated with an organic compound, it is difficult to ensure stability and dispersibility in water-based inks. In addition, when printing on fiber structures, it is difficult to fully cover the color of the fibers.

The present invention aims to provide an aqueous inkjet ink suitable for inkjet printing of a structure composed of cotton or synthetic fibers. In addition, the present invention aims to provide a method for printing a fiber structure by an inkjet method, which has excellent OD, penetration suppression or color development after printing.

Means of solving the problem:

The present inventors have continued to study color or black aqueous inkjet inks suitable for printing fiber structures, especially structures composed of polyester fibers, by an inkjet method. As a result, they found that by combining a pigment and a dispersant having a cationic functional group in a specific ratio, a printed material with an excellent OD value after printing on an anionized structure can be obtained, thereby completing the present invention.

In addition, in order to solve the above-mentioned problems, the present inventors have continuously studied white water-based inkjet ink containing titanium oxide as a white pigment, and found that the stability and dispersibility of the white pigment can be improved by combining surface-treated titanium oxide as a white pigment and a cationic dispersant having a specific amine value and an acid value in a specific ratio. In addition, the present inventors found that using such a white water-based inkjet ink, a printed material having excellent hiding power (color development) after printing on a fiber structure can be obtained, thereby completing the present invention.

Specifically, the present invention relates to an aqueous inkjet ink, which is an aqueous 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 an amine value higher than an acid value.

The content of the pigment is 0.01 mass % or more and 30 mass % or less,

The value of the dispersant content/the pigment content×100 is 5 or more and 200 or less,

Ink for printing on structures made of cotton or synthetic fibers.

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

Preferably, the dispersant is a cationic dispersant having an amine value of 60 mgKOH/g to 150 mgKOH/g and an acid value of 0 mgKOH/g. Here, "acid value of 0 mgKOH/g" means that the acid value includes not only the case of 0 mgKOH/g, but also the case below the measurement limit in the usual acid value measurement method.

Preferably, the synthetic fibers are polyester fibers.

Preferably, the polyester fiber is anionized polyester.

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

Preferably, for a white pigment, the pigment is titanium oxide surface-treated with aluminum oxide, silicon dioxide, polyol and/or polysiloxane.

In a white aqueous inkjet ink containing titanium oxide as a white pigment, the use of only the surface-treated titanium oxide disclosed in Patent Documents 4 or 5 cannot improve the stability and dispersibility of the titanium oxide particles. In addition, depending on the type of dispersant used simultaneously, there are cases where the color development (hiding property) is insufficient when printing on a fiber structure. However, a white aqueous inkjet ink containing a specific surface-treated titanium oxide and a specific cationic dispersant in a specific ratio has excellent color development (hiding property) even when printing on a fiber structure, and the stability and dispersibility of the titanium oxide particles in the white aqueous inkjet ink should also be excellent.

Preferably, in the case of an aqueous inkjet ink containing a white pigment, (dispersant concentration (mass %)/titanium oxide concentration (mass %))×amine value (mgKOH/g) in the aqueous inkjet ink=2.50 to 8.50.

Furthermore, the present invention relates to a method,

It is a method of printing a fiber structure composed of synthetic fibers by inkjet method.

The method has:

Step A of performing anionization treatment on the fiber structure using an anionization treatment agent; and

After step A, step B is to print the fiber structure by inkjet method using water-based inkjet ink, wherein the water-based inkjet ink 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 an amine value higher than an acid value.

The content of the pigment is 0.01 mass % or more and 30 mass % or less,

The value of the dispersant content/the pigment content×100 is 5 or more and 200 or less.

Furthermore, the present invention relates to a method,

It is a method of printing a fiber structure made of cotton material by inkjet method.

The method has:

Step B of printing the fiber structure by inkjet method using aqueous inkjet ink,

The aqueous inkjet ink 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 an amine value higher than an acid value.

The content of the pigment is 0.01 mass % to 30 mass %, and the value of the dispersant content/the pigment content×100 is 5 to 200.

Effect of the invention:

According to the present invention, when a structure composed of synthetic fibers subjected to anionization treatment is subjected to inkjet printing in color or black, the OD after printing can be increased and bleeding can be prevented.

In addition, according to the present invention, in a white aqueous inkjet ink containing surface-treated titanium oxide particles as a white pigment, the stability and dispersibility of the pigment particles can be improved. According to the present invention, when a structure composed of synthetic fibers treated with anionization is inkjet printed with white, the color rendering after printing can be improved.

DETAILED DESCRIPTION

Embodiments of the present invention are described below.

[pigment]

The color or black pigment that can be used in the present invention is not particularly limited, and for example, carbon black, titanium black, C.I. 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-131, PY-132, PY-133, PY-134, PY-135, PY-136, PY-137, PY-138, PY-139, PY-240, PY-241, PY-242, PY-243, PY-244, PY-245, PY-246, PY-247, PY-248, PY-249, PY-250, PY-251, PY-252, PY-253, PY-254, PY-255, PY-256, PY-257, PY-258, PY-259, PY-260, PY-261, PY-263, PY-264, PY-265 Y-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-23 7, 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, PO-73, etc., but not limited to these. These pigments can be used alone or in combination of two or more.

The average particle size (average particle size of primary particles) of the color or black pigment in the aqueous inkjet ink of the present invention is preferably 10 to 250 nm based on the sedimentation of the color 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 sedimentation of the pigment particles.

The average particle size here refers to the average value of the major diameter and minor diameter when observing more than 100 pigment particles using a transmission electron microscope (the average value of the measured number of particles of major diameter (nm) + minor diameter (nm)/2 of one particle). The same applies to the average particle size of the surface-treated titanium oxide described later.

The white pigment that can be used in the present invention is titanium oxide surface-treated with aluminum oxide, silicon dioxide, polyol and/or polysiloxane.

As titanium oxide, anatase or rutile can be used, but rutile is preferred because of its higher hiding power for printed materials. In addition, titanium oxide prepared by a known preparation method such as the chlorine method or the sulfuric acid method can be used, but titanium oxide prepared by the chlorine method with higher whiteness is preferred.

Untreated titanium oxide has numerous hydroxyl groups on its surface, which are responsible for its hydrophilicity. Hydroxyl groups are removed from the titanium oxide surface by reacting with polyols or polysiloxanes, which are organic compounds, and then covered with polyols or polysiloxanes, thereby making the titanium oxide hydrophobic.

In Patent Document 4, the organic compound for surface treatment of titanium oxide is not particularly limited as long as it can make titanium oxide hydrophobic, and examples thereof include polyols, alkanolamines or derivatives thereof, organosilicon compounds, higher fatty acids or metal salts thereof, and organometallic compounds.

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

On the other hand, the surface-treated titanium oxide used in the present invention is titanium oxide surface-treated with three components: (1) aluminum oxide, (2) silicon dioxide, and (3) polyol and/or polysiloxane, which are organic compounds.

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 based on the sedimentation 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, it is not easy to cause sedimentation of titanium oxide, but the hiding power decreases, and the practicality as a white inkjet ink decreases. On the other hand, if it exceeds 400 nm, the hiding power is sufficient, but it is easy to cause sedimentation. The average particle size of the surface-treated titanium oxide is more preferably 150 to 350 nm, and further preferably 200 nm to 300 nm.

[Dispersant]

The dispersant used in the present invention is a cationic dispersant having an amine value of 10 mgKOH/g or more and an amine value higher than an 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. The dispersant may be used alone or in combination of two or more.

Here, the amine value means the amine value per 1 g of the dispersant solids, and is a value obtained by potentiometric titration using a 0.1 N hydrochloric acid aqueous solution and converted into an equivalent of potassium hydroxide (unit: mgKOH/g). In addition, the acid value means the acid value per 1 g of the dispersant solids, and can be obtained by potentiometric titration according to JIS K 0070 (1992) (unit: mgKOH/g).

There are many cationic dispersants on the market that have an amine value of 10 mgKOH/g or more and an amine value higher than an acid value, for example, DISPERBYK-182, 183, 184, 185, 191, 2013, 2050, 2070, 2055, BYKJET-9151, 9152, 9171 (all produced by BYK JAPAN), EFKAPX-4330, 4350, 4701, 4703, 4733, 4753, 4780 (all produced by BASF), TEGO Dispers 650 (produced by Evonik), etc. These dispersants may be used alone or in combination of two or more.

In the present invention, the value of (dispersant concentration (mass %)/titanium oxide concentration (mass %))×amine value (mgKOH/g) in the white aqueous 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 solid matter as a dispersant contained in the aqueous inkjet ink. In addition, "titanium oxide concentration (mass %)" refers to the concentration of surface-treated titanium oxide contained in the aqueous inkjet ink.

The solvent that can be used in the present invention is not particularly limited, and examples thereof include monohydric alcohols such as methanol, ethanol, and isopropanol; polyhydric alcohols; ketones or ketoalcohols such as acetone and diacetone alcohol; and cyclic ethers such as tetrahydrofuran and dioxane.

The aqueous inkjet ink of the present invention may further contain additives such as pH adjusters, surfactants, chelating agents, rust inhibitors, antioxidants, ultraviolet absorbers, preservatives, antifungal agents, defoamers, etc. as needed. The content (concentration) of these additives may be adjusted within the range in which they can exert their functions.

The pH adjuster that can be used in the present invention is not particularly limited, and examples thereof include alkali metal hydroxides such as sodium oxide, potassium hydroxide, and lithium hydroxide; tertiary amines such as triethanolamine, diethanolamine, dimethylethanolamine, and diethylethanolamine; ammonia water, hydrochloric acid, acetic acid, and formic acid.

The surfactant that can be used in the present invention is not particularly limited, and examples thereof include anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, fluorine-containing surfactants, silicone surfactants, and the like.

The aqueous inkjet ink of the present invention can be obtained by preparing a pigment dispersion (pigment dispersion), adding a solvent and an additive thereto, and mixing. The pigment dispersion can be obtained by mixing a pigment and a dispersion, and dispersing the mixture using a sand mill (bead mill), a roller mill, a ball mill, a paint stirrer, an ultrasonic disperser, a high-pressure emulsifier, and the like.

The aqueous inkjet ink of the present invention can be obtained by preparing a pigment dispersion (pigment dispersion), adding a solvent and an additive thereto, and mixing. The pigment dispersion can be prepared by mixing a pigment and a dispersion, and dispersing the mixture using a sand mill (bead mill), a roller mill, a ball mill, a paint stirrer, an ultrasonic disperser, a high-pressure emulsifier, and the like.

As an example, the case of performing a dispersion treatment using a sand mill is described. First, the pigment, dispersant, and beads of the dispersion medium are loaded into a sand mill. As beads, glass beads, zirconium oxide beads, etc. with a particle size of 0.01 to 1 mm can be used. The amount of beads used is preferably 2 to 6 weights per 1 weight of ink. After that, the sand mill is operated for dispersion treatment. The dispersion treatment conditions are preferably about 1000 to 2000 rpm for 1 to 20 hours. After the dispersion treatment, the beads and the like are removed by filtration to obtain a pigment dispersion.

The pigment concentration (mass %) in the aqueous inkjet ink of the present invention is preferably 0.01 mass % to 30 mass % for any one of the color, black or white pigments, more preferably 0.01 mass % to 20 mass %, and further preferably 1 mass % to 15 mass %. Within this range, sufficient color development (hiding property) can be obtained, and there is also a tendency that the storage stability of the ink is excellent.

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

＜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 produced by Sanyo Pigment Co., Ltd.) as a cyan pigment, 11.5 parts by weight of dispersant C (DISPERBYK-185 (produced by BYK JAPAN / amine value = 17 mgKOH/g, active ingredient 52%) as a 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 placed in a sand mill and dispersed at 1,500 rpm for 3 hours. Thereafter, the zirconia beads were removed to obtain a pigment dispersion. In addition, the particle size of the pigment and the dispersant was adjusted to about 100 to 110 nm.

In the pigment dispersion, BYK-348 (polyether-modified siloxane produced by BYK JAPAN) as a surfactant, formic acid or triethanolamine as a pH adjuster, 1,2-hexanediol as a solvent, glycerin, and deionized water were mixed as shown in Table 1 to prepare a cyan ink with a pH of 9. In addition, the aqueous 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.

[Table 1]

(Example 2/magenta ink)

A magenta ink was prepared in the same manner as in Example 1 except that FASTOGEN SUPER MAGENTARG (PR-122 manufactured by DIC Corporation) was used as the magenta pigment.

(Example 3/yellow ink)

A yellow ink was prepared in the same manner as in Example 1 except that Inkjet Yellow 4GC (PY-155 manufactured by Clariant) was used as the yellow pigment.

(Example 4/black ink)

A black ink was prepared in the same manner as in Example 1 except that NIPex 160IQ (carbon black produced by Orion Engineered Carbons) was used as the black pigment.

(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 (produced by BASF, amine value = 40 mgKOH/g, active ingredient 100%)) was used as the dispersant and 79.0 parts by weight of deionized water was used.

(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 (produced 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 deionized water was used.

(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 (produced by BYK JAPAN, amine value = 19 mgKOH/g, acid value = 6 mgKOH/g, active ingredient 100%)) was used as the dispersant and 79.0 parts by weight of deionized water was used.

(Example 8/cyan ink)

A cyan ink was prepared in the same manner as in Example 1 except that the amount of dispersant C and the amount of deionized water was changed to 8.7 parts by weight and 76.3 parts by weight.

(Example 9/cyan ink)

A cyan ink was prepared in the same manner as in Example 1 except that the amount of dispersant C and the amount of deionized water was changed to 17.3 parts by weight and 67.7 parts by weight.

(Example 10/cyan ink)

A cyan ink was prepared in the same manner as in Example 1 except that 37.5 parts by weight of a dispersant A (amine value: 67 mgKOH/g, solid content: 20%) described below was used as the dispersant and 47.5 parts by weight of deionized water was used.

(Example 11/cyan ink)

A cyan ink was prepared in the same manner as in Example 1 except that 37.5 parts by weight of a dispersant B (amine value: 135 mgKOH/g, solid content: 20%) described below was used as the dispersant and 47.5 parts by weight of deionized water was used.

[Preparation method of dispersant A]

A resin having 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 deionized water were added to the resin to dissolve it, and the solid content was adjusted to 20% to obtain a dispersant A.

[Preparation method of dispersant B]

A resin having a monomer composition ratio of benzyl methacrylate/dimethylaminoethyl methacrylate = 60/40 (mass ratio) and an amine value of 135 mgKOH/g was prepared. To the resin, formic acid and a deionized solution were added to adjust the solid content to 20% to obtain a dispersant B.

(Comparative Example 1/cyan ink)

A cyan ink was prepared in the same manner as in Example 1 except that the amount of dispersant F (DISPERBYK-190 (manufactured by BYK JAPAN, acid value = 10 mgKOH/g, active ingredient 40%)) was 15.0 parts by weight and the amount of deionized water was 70.0 parts by weight.

(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 (produced by BASF, acid value = 213 mgKOH/g, active ingredient 30%)) and 65.0 parts by weight of deionized water were used as the dispersant.

(Comparative Example 3/magenta ink)

A magenta ink was prepared in the same manner as in Example 2 except that the amount of the dispersant F was 15.0 parts by weight and the amount of deionized water was 70.0 parts by weight.

(Comparative Example 4/magenta ink)

A magenta ink was prepared in the same manner as in Example 2 except that the amount of dispersant J was 20.0 parts by weight and the amount of deionized water was 65.0 parts by weight.

(Comparative Example 5/yellow ink)

A yellow ink was prepared in the same manner as in Example 3 except that the amount of the dispersant F was 15.0 parts by weight and the amount of deionized water was 70.0 parts by weight.

(Comparative Example 6/yellow ink)

A yellow ink was prepared in the same manner as in Example 3 except that the amount of dispersant J was 20.0 parts by weight and the amount of deionized water was 65.0 parts by weight.

(Comparative Example 7/black ink)

A black ink was prepared in the same manner as in Example 4 except that the amount of the dispersant F was 15.0 parts by weight and the amount of deionized water was 70.0 parts by weight.

(Comparative Example 8/black ink)

A black ink was prepared in the same manner as in Example 4 except that the amount of dispersant J was 20.0 parts by weight and the amount of deionized water was 65.0 parts by weight.

(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 (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 deionized water was used.

(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 deionized water was used.

＜Fiber structure＞

As the fiber structures for printing samples, the following three samples were used:

·Cotton material structure: 100% pure cotton fabric (broad cotton cloth produced by dyeing company without mercerization treatment);

Polyester structure (untreated polyester structure): polyester 100% cotton (Amina produced by Toray);

· Anionized polyester structure (anionized polyester structure): a structure obtained by treating the same structure as the polyester structure with an anionizing agent.

<Anionization treatment method/step A>

A cationic polymerizer (cationic polymer compound/Sanyo Pigment Co., Ltd., cationizing agent CTF1101) was made to adhere to the polyester structure as a 6 g/L prepared liquid through 1DIP/1NIP, and then dried at 130°C for 3 minutes. Next, an anionic polymerizer was made to adhere as a 60 g/L prepared liquid through 1DIP/1NIP, and then dried at 130°C for 3 minutes to obtain an anionized polyester structure.

Here, the "anionization treatment" in the present invention refers to attaching an anionic polymerizer to a structure composed of synthetic fibers. The anionic polymerizer can be selected from anionic polyester resins, anionic surfactants, polyester emulsions, etc., among which polyester emulsions are preferred. Polyester resins that can be used for polyester emulsions include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, etc., and refers to a substance that is emulsified with an activator.

In addition, preferably, before such treatment, a cationic polymerization agent is used to perform a cationization treatment. Here, as the cationic polymerization agent, a known polymer (polymer or prepolymer) containing a tertiary amino group or a quaternary ammonium group or both in the molecule can be used, and in addition, a cationic compound generally used as a cationizing agent can also be used.

Examples of polymers containing tertiary amino groups include the following polymers: (a) polymers of alkylaminoalkyl (meth)acrylamide, for example, polymers of dimethyl or diethylaminoethyl (meth)acrylamide, dimethyl or diethylaminopropyl (meth)acrylamide, etc.; (b) polymers of dialkylaminoalkyl (meth)acrylate, for example, polymers of dimethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethyl (meth)acrylate, diethylaminopropyl (meth)acrylate, etc.; (c) acrylamide styrene copolymers; (d) urethane polymers containing tertiary amino groups, etc.

Examples of polymers containing quaternary ammonium groups include the following polymers: (e) polymers of (meth)acryloyloxyalkyltrialkylammonium salts, for example, polymers of 2-(meth)acryloyloxyethyltrimethylammonium chloride and 3-(meth)acryloyloxy-2-hydroxypropyltrimethylammonium chloride; (f) polymers of (meth)acrylamidealkyltrialkylammonium salts, for example, polymers of (3-(meth)acrylamidepropyltrimethylammonium chloride and 3-(meth)acrylamide-2-hydroxypropyltrimethylammonium chloride; (g) polymers of 2-(meth)acryloyloxyalkylbenzylammonium salts, for example, 2-(meth)acryloyloxyethylbenzylammonium chloride or Polymers of 2-(meth)acryloyloxyethyldimethylbenzyl ammonium chloride, copolymers of monomers of acryloyloxyethylbenzyl ammonium chloride or 2-(meth)acryloyloxyethyldimethylbenzyl ammonium chloride with acrylamide, dimethylaminoethyl acrylate, etc.; (h) copolymers of acrylamidopropyldimethylbenzyl chloride with N,N-dimethylacrylamide and N-methyl-N-benzyl allylamine salt with N-methyl-N-hydroxyethylaminopropyl acrylamide, etc.; (i) other polymers such as dimethyl or diethyl diallyl ammonium chloride, β-vinyloxyethyl trialkylammonium salt, vinylbenzyl ammonium salt, etc.

In addition, as cationic compounds, (j) compounds containing quaternary ammonium groups can be used, for example, 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-epoxypropyldimethylammonium chloride), 3-chloro-2-hydroxypropyl-trimethylammonium chloride, 2,3-epoxypropyltrimethylammonium chloride, etc., among which polydialkylamino(meth)acrylates, polydimethyldiallylammonium chloride, and urethane polymers containing tertiary amino groups are preferred.

In addition, the anionization treatment in the present invention is not limited to the treatment described in the step A described later.

<Printing of fiber structure/step B>

Three types of fiber structures were used as printing objects, and printing was performed using an inkjet printer with a resolution of 600 dpi using the prepared aqueous inkjet ink to form a solid image.

＜OD value measurement method＞

The optical density of the obtained solid image surface was measured by a reflection densitometer GretagMacbeth RD-19 (SAKATA INX CORPORATION).

＜Infiltration＞

With respect to the obtained solid image, the distance at which the ink bleeds the most is measured with a ruler.

Regarding the aqueous inkjet inks of cyan, magenta, yellow and black, the results of OD value, OD evaluation and penetration evaluation are shown in Tables 2 to 5, respectively. Here, in Tables 2 to 5, for the OD evaluation of yellow, cyan and black, OD values of 1.15 or more are evaluated as "◎", 1.10 or more are evaluated as "○", 1.05 or more and less than 1.10 are evaluated as "△", and less than 1.05 are evaluated as "×", and for magenta, OD values of 1.00 or more are evaluated as "○", and less than 1.00 are evaluated as "△". In addition, for the penetration evaluation, the four colors are the same, and the ink seepage distance is less than 1mm. It is evaluated as "○", 1mm or more and less than 2mm is evaluated as "△", and 2mm or more is evaluated as "×". This evaluation is also the same in Tables 6 to 8 described later.

[Table 2]

[Table 3]

[Table 4]

[Table 5]

For the structure of cotton material, the OD evaluation and penetration evaluation of the ink using dispersant C (Examples 1 to 4) were "○" for all colors. On the other hand, when dispersant F (Comparative Examples 1, 3, 5, 7) or dispersant J (Comparative Examples 2, 4, 6, 8) was used as the dispersant, the OD evaluation or penetration evaluation was "×", which was judged to be lacking in practicality.

For the structure of untreated polyester, the OD evaluation or penetration evaluation was "×" for all colors and practically all dispersants, which was judged to be lacking in practicality. However, for the structure of anionized polyester (indicated as treated polyester in Tables 2 to 5) after the same structure was anionized, the OD evaluation and penetration evaluation of the ink (Examples 1 to 4) using dispersant C were "○" for all colors.

The OD values, OD evaluation, and penetration evaluation results of the cyan aqueous inkjet inks of Examples 5 to 7 are shown in Table 6. Examples 5 to 7 using Dispersant D, Dispersant E, and Dispersant I as the dispersant used in the pigment dispersion obtained the same results as Example 1.

[Table 6]

The OD values, OD evaluations, and penetration evaluations of the cyan aqueous inkjet inks 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 material or the anionized polyester can be determined as “○”.

[Table 7]

The OD values, OD evaluation, and penetration evaluation results of the cyan aqueous inkjet inks of Examples 10 to 11 and Comparative Examples 9 and 10 are shown in Table 8. The OD evaluation of Examples 10 to 11 using Dispersant A and Dispersant B as the dispersant used in the pigment dispersion was "◎" and the penetration evaluation was "○", which was the best among the Examples.

[Table 8]

Thus, it can be confirmed that the aqueous inkjet ink of the present invention containing a pigment and a specific cationic dispersant is more suitable for printing on a fiber structure composed of cotton or anionized polyester fiber than an aqueous inkjet ink containing the same pigment and other dispersants.

It can be determined from Tables 2 to 8 that in the case of an aqueous inkjet ink containing a color or black pigment, the dispersant is preferably a "cationic dispersant having an amine value of 10 mgKOH/g or more, and an amine value higher than the acid value", and more 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" such as dispersant A and dispersant B.

＜Preparation of water-based inkjet ink 2: White＞

(Example 12)

40.0 parts by weight of TIPAQUE PF-728 (produced by Ishihara Sangyo Co., Ltd., alumina/silica/polysiloxane treatment) as titanium oxide, 20.0 parts by weight of dispersant A as a dispersant, 40.0 parts by weight of deionized water, and 400 parts by weight of zirconia beads having a diameter of 0.5 mm were placed in a sand mill and dispersed at 1,500 rpm for 2 hours. Thereafter, the zirconia beads were removed to obtain a titanium oxide dispersion.

The titanium oxide dispersion, BYK-348 (polyether-modified siloxane produced by BYK JAPAN) as a surfactant, 1,2-hexanediol as a solvent, glycerin, and deionized water were mixed in the amounts shown in Table 9 to prepare the white ink of Example 12. In addition, the aqueous inkjet inks of Examples 12 to 25 and Comparative Examples 11 to 27 were adjusted to a total amount of 100.0 parts by weight.

[Table 9]

Titanium oxide dispersion 25.0 parts by weight 1,2-Hexanediol 1.0 parts by weight glycerin 13.0 parts by weight BYK-348 0.3 parts by weight Deionized water The remainder total 100.0 parts by weight

.

(Example 13)

A titanium oxide dispersion was obtained 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 deionized water was used. Then, a white ink of Example 13 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Example 14)

A titanium oxide dispersion was obtained in the same manner as in Example 1 except that 15.3 parts by weight of dispersant C (DISPERBYK-185 produced by BYK JAPAN, amine value 17 mgKOH/g, solid content 52%) was used as the dispersant and 44.7 parts by weight of deionized water was used. Then, a white ink of Example 3 was prepared in the same manner as in Example 1 at the dosages shown in Table 9.

(Example 15)

A titanium oxide dispersion was obtained 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 deionized water was used. Then, a white ink of Example 15 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Example 16)

A titanium oxide dispersion was obtained 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 deionized water was used. Then, a white ink of Example 16 was prepared in the same manner as in Example 1 at the blending amounts shown in Table 9.

(Example 17)

A titanium oxide dispersion was obtained in the same manner as in Example 12 except that TIPAQUE PF-740 (manufactured by Ishihara Sangyo Co., Ltd., alumina/zirconia/silica/polysiloxane treatment) was used at 40.0 parts by weight. Then, a white ink of Example 17 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Example 18)

A titanium oxide dispersion was obtained in the same manner as in Example 15 except that TIPAQUE PF-740 was used in an amount of 40.0 parts by weight. Then, a white ink of Example 18 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Example 19)

A titanium oxide dispersion was obtained in the same manner as in Example 12 except that 40.0 parts by weight of TIPAQUE CR-63 (produced by Ishihara Sangyo Co., Ltd., alumina/silica/polyol/polysiloxane treatment) was used as titanium oxide. Then, a white ink of Example 19 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Example 20)

A titanium oxide dispersion was obtained in the same manner as in Example 15 except that 40.0 parts by weight of TIPAQUE CR-63 was used as titanium oxide. Then, a white ink of Example 20 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Example 21)

A titanium oxide dispersion was obtained in the same manner as in Example 12 except that 40.0 parts by weight of TIPAQUE PF-671 (manufactured by Ishihara Sangyo Co., Ltd., alumina/silica/polyol treatment) was used as titanium oxide. Then, a white ink of Example 21 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Example 22)

A titanium oxide dispersion was obtained in the same manner as in Example 15 except that 40.0 parts by weight of TIPAQUE PF-671 was used as titanium oxide. Then, a white ink of Example 22 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Example 23)

A titanium oxide dispersion was obtained in the same manner as in Example 12 except that the amount of dispersant A was 10.0 parts by weight and the amount of deionized water was 50.0 parts by weight. Then, a white ink of Example 23 was prepared in the same manner as in Example 12 at the amounts shown in Table 9.

(Example 24)

A titanium oxide dispersion was obtained 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 deionized water was 54.0 parts by weight. Then, a white ink of Example 13 was prepared in the same manner as in Example 12 at the amounts shown in Table 9.

(Example 25)

A titanium oxide dispersion was obtained in the same manner as in Example 15 except that the amount of dispersant D was 8.0 parts by weight and the amount of deionized water was 52.0 parts by weight. Then, a white ink of Example 25 was prepared in the same manner as in Example 12 at the amounts shown in Table 9.

(Comparative Example 11)

A titanium oxide dispersion was obtained in the same manner as in Example 12 except that 40.0 parts by weight of TIPAQUE PF-726 (manufactured by Ishihara Sangyo Co., Ltd., treated with alumina/silica) was used as titanium oxide. Then, a white ink of Comparative Example 11 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 12)

A titanium oxide dispersion was obtained in the same manner as in Example 13 except that 40.0 parts by weight of TIPAQUE PF-726 was used as titanium oxide. Then, a white ink of Comparative Example 12 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 13)

A titanium oxide dispersion was obtained in the same manner as in Example 14 except that 40.0 parts by weight of TIPAQUE PF-726 was used as titanium oxide. Then, a white ink of Comparative Example 13 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 14)

A titanium oxide dispersion was obtained in the same manner as in Example 15 except that TIPAQUE PF-726 was used as 40.0 parts by weight. Then, a white ink of Comparative Example 14 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 15)

A titanium oxide dispersion was obtained in the same manner as in Example 16 except that 40.0 parts by weight of TIPAQUE PF-726 was used as titanium oxide. Then, a white ink of Comparative Example 15 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 16)

A titanium oxide dispersion was obtained in the same manner as in Example 12 except that 40.0 parts by weight of TIPAQUE CR-50 (manufactured by Ishihara Sangyo Co., Ltd., treated with alumina) was used as titanium oxide. Then, a white ink of Comparative Example 16 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 17)

A titanium oxide dispersion was obtained in the same manner as in Example 15 except that 40.0 parts by weight of TIPAQUE CR-50 was used as titanium oxide. Then, an ink of Comparative Example 17 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 18)

A titanium oxide dispersion was obtained in the same manner as in Example 12 except that 40.0 parts by weight of TIPAQUE CR-50-2 (manufactured by Ishihara Sangyo Co., Ltd., alumina/polyol treated) was used as titanium oxide. Then, a white ink of Comparative Example 18 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 19)

A titanium oxide dispersion was obtained in the same manner as in Example 15 except that 40.0 parts by weight of TIPAQUE CR-50-2 was used as titanium oxide. Then, a white ink of Comparative Example 19 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 20)

A titanium oxide dispersion was obtained 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 deionized water was used. Then, a white ink of Comparative Example 20 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 21)

A titanium oxide dispersion was obtained 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 deionized water was used. Then, a white ink of Comparative Example 21 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 22)

A titanium oxide dispersion was obtained 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 deionized water was used. Then, a white ink of Comparative Example 22 was prepared in the same manner as in Example 12 at the blending amounts shown in Table 9.

(Comparative Example 23)

A titanium oxide dispersion was obtained in the same manner as in Example 12 except that the amount of dispersant A was 6.0 parts by weight and the amount of deionized water was 54.0 parts by weight. Then, a white ink of Comparative Example 23 was prepared in the same manner as in Example 12 at the amounts shown in Table 9.

(Comparative Example 24)

A titanium oxide dispersion was obtained in the same manner as in Example 1 except that the amount of dispersant A and the amount of deionized water were 30.0 parts by weight. Then, a white ink of Comparative Example 14 was prepared in the same manner as in Example 1 at the amounts shown in Table 9.

(Comparative Example 25)

A titanium oxide dispersion was obtained in the same manner as in Example 13 except that the amount of dispersant B was 16.0 parts by weight and the amount of deionized water was 44.0 parts by weight. Then, a white ink of Comparative Example 25 was prepared in the same manner as in Example 12 at the amounts shown in Table 9.

(Comparative Example 26)

A titanium oxide dispersion was obtained in the same manner as in Example 15 except that the amount of dispersant D was 2.0 parts by weight and the amount of deionized water was 58.0 parts by weight. Then, a white ink of Comparative Example 26 was prepared in the same manner as in Example 12 at the amounts shown in Table 9.

(Comparative Example 27)

A titanium oxide dispersion was obtained in the same manner as in Example 15 except that the amount of dispersant D was 10.0 parts by weight and the amount of deionized water was 50.0 parts by weight. Then, a white ink of Comparative Example 27 was prepared in the same manner as in Example 12 at the amounts shown in Table 9.

＜Stability test＞

Take 10g of the white ink of Examples 12 to 25 and Comparative Examples 10 to 27 into a sealed container and place it in a constant temperature device at 60°C for 1 week. After cooling to room temperature, use a light scattering photometer and an E-type viscometer to measure the average particle size (the average particle size of titanium oxide particles as a pigment) and viscosity in the white ink. The average particle size (the average particle size of titanium oxide particles as a 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 value by the following calculation formula:

Increase rate (%) = (B-A)/A×100.

Then, the calculated increase rate was evaluated for the stability of each white ink based on the following evaluation criteria. In addition, "△" or above is a level with practical use:

○: The increase rate of both the average particle size and the viscosity is less than 10%;

△: The increase rate of either the average particle size or the viscosity is 10% or more;

×: The increase rates of both the average particle size and the viscosity were 10% or more.

＜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 left to stand in a constant temperature device at 25°C for 3 days. Thereafter, the sedimentation of each white ink was evaluated based on the following evaluation criteria. In addition, "○" indicates a level of practical applicability:

○: No sediment was confirmed in the lower part of the glass container;

×: Sediment was observed at the bottom of the glass container.

<Anionization treatment method/step A>

According to step A of the preparation 1 of the aqueous inkjet ink, an anionized polyester structure is obtained.

<Printing of fiber structure/step B>

For the white inks of Examples 12 to 25 and Comparative Examples 10 to 27, solid printing was performed on the following substrates using a printer with a resolution of 600 dpi:

Substrate 1: black cotton cloth (H.444 produced by Kurabo);

Substrate 2: Black polyester fabric after the above anionization treatment.

＜Hiding test＞

For substrates 1 and 2, the OD value of the obtained image surface was measured using a reflection densitometer (GretagMacbeth RD-19, SAKATA INX CORPORATION), and the hiding power was calculated based on the following calculation formula: hiding power (%) = (1-OD of printed material/OD of black cotton cloth before printing) × 100.

Then, the hiding power of each white ink was evaluated based on the following evaluation criteria. In addition, "△" or above is a level with practical application:

◎: Covering capacity more than 70%;

○: Covering power is more than 50% and less than 70%;

△: covering power is more than 30% and less than 50%;

×: The hiding power is less than 30%.

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

[Table 10]

[Table 11]

According to Table 10, all evaluation items of the white inks of Examples 12 to 25 are "practical". In addition, except for Example 16, all evaluation items are "○" or above. In addition, the stability and sedimentation of Examples 12, 13, 17, 19, 21, 23, and 24 are "○", and the hiding power is "◎", which is particularly excellent. On the other hand, according to Table 11, the white inks of Comparative Examples 10 to 27 all have one evaluation item "×", which is judged to be not practical.

Here, in the case of the white ink of Example 12, the dispersant in 25.0 parts by weight of the titanium oxide dispersion is 20.0×(25/100) parts by weight, and the solid content of the dispersant is 20.0×(25/100)×0.2 parts by weight. The titanium oxide in 25.0 parts by weight of the titanium oxide dispersion is 40.0×(25/100) parts by weight. Since the total amount of the white ink is 100 parts by weight, the (dispersant concentration (mass %)/titanium oxide concentration (mass %))×amine value (mgKOH/g) in the white ink (aqueous 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 in the same manner as (dispersant concentration (mass %)/titanium oxide concentration (mass %))×amine value (mgKOH/g).

From Tables 10 and 11, it can be determined that white inks with excellent stability, sedimentation and hiding power meet the following conditions: (i) titanium oxide surface-treated with aluminum oxide, silicon dioxide, polyol and/or polysiloxane is used as the white pigment; (ii) the amine value of the cationic dispersant is 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. In addition, it is considered that the value of (dispersant concentration (mass %)/titanium oxide concentration (mass %))×amine value (mgKOH/g) is preferably 3.20 to 8.20, and more preferably 3.20 to 7.00. It is considered that the cationic dispersant preferably has a value of 60 mgKOH/g to 150 mgKOH/g, and an acid value of 0 mgKOH/g.

As described above, it can be determined that the water-based inkjet ink of the present invention containing a pigment and a specific cationic dispersant is more suitable for printing on a fiber structure composed of cotton or anionized polyester fiber than a water-based inkjet ink containing the same pigment and other dispersants. In addition, when the water-based inkjet ink of the present invention is a water-based ink containing surface-treated titanium oxide as a white pigment, the stability and dispersibility of the pigment particles are excellent. In addition, when the fiber structure is subjected to the printing, the color of the fiber can be fully covered.

Industrial Applicability:

The aqueous inkjet ink and the method for printing a fiber structure by an inkjet method of the present invention are useful in the field of printing.

Claims (15)

1. A water-based inkjet ink, It is an aqueous 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 an amine value higher than an acid value. The content of the pigment is 0.01 mass % to 30 mass %, The value of the dispersant content/the pigment content×100 is 5 or more and 200 or less, Ink for printing on structures made of cotton or synthetic fibers. 2. The aqueous inkjet ink according to claim 1, characterized in that: The dispersant is a cationic dispersant having an amine value of 60 mgKOH/g to 150 mgKOH/g and an acid value of 0 mgKOH/g. 3. The aqueous inkjet ink according to claim 1 or 2, characterized in that: The synthetic fiber is polyester fiber. 4. The aqueous inkjet ink according to claim 3, characterized in that: The polyester fiber is anionized polyester. 5. The aqueous inkjet ink according to any one of claims 1 to 4, characterized in that The pigment is any one of Pigment Yellow 155, Pigment Red 122, Pigment Blue 15:3, and Pigment Black 7. 6. The aqueous inkjet ink according to any one of claims 1 to 4, characterized in that The pigment is titanium oxide surface-treated with aluminum oxide, silicon dioxide, polyol and/or polysiloxane. 7. The aqueous inkjet ink according to claim 6, characterized in that: In the aqueous inkjet ink, (dispersant concentration (mass %)/titanium oxide concentration (mass %))×amine value (mgKOH/g)=2.50 to 8.50. 8. A method, It is a method of printing a fiber structure composed of synthetic fibers by inkjet method. The method has: A step A of anionizing the fiber structure using an anionizing agent, and After step A, step B of printing the fiber structure by inkjet method using aqueous inkjet ink, The aqueous inkjet ink 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 an amine value higher than an acid value. The content of the pigment is 0.01 mass % to 30 mass %, The value of the dispersant content/the pigment content×100 is 5 or more and 200 or less. 9. A method, It is a method of printing a fiber structure made of cotton material by inkjet method. The method comprises a step B of printing a fiber structure by an inkjet method using an aqueous inkjet ink, The aqueous inkjet ink 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 an amine value higher than an acid value. The content of the pigment is 0.01 mass % or more and 30 mass % or less, The value of the dispersant content/the pigment content×100 is 5 or more and 200 or less. 10. The method according to claim 8 or 9, characterized in that: The dispersant is a cationic dispersant having an amine value of 60 mgKOH/g to 150 mgKOH/g and an acid value of 0 mgKOH/g. 11. The method according to claim 8 or 10, characterized in that: The synthetic fiber is polyester fiber. 12. The method according to claim 8, 10 or 11, characterized in that The anionizing agent is a polyester emulsion. 13. The method according to any one of claims 8 to 12, characterized in that The pigment is any one of Pigment Yellow 155, Pigment Red 122, Pigment Blue 15:3 or Pigment Black 7. 14. The method according to any one of claims 8 to 12, characterized in that The pigment is titanium oxide surface-treated with aluminum oxide, silicon dioxide, polyol and/or polysiloxane. 15. The aqueous inkjet ink according to claim 14, characterized in that: In the aqueous inkjet ink, (dispersant concentration (mass %)/titanium oxide concentration (mass %))×amine value (mgKOH/g)=2.50 to 8.50.