WO2016125869A1

WO2016125869A1 - Inkjet ink, inkjet printing method, fabric printed by inkjet printing method, and inkjet printing system

Info

Publication number: WO2016125869A1
Application number: PCT/JP2016/053410
Authority: WO
Inventors: 金子　学
Original assignee: コニカミノルタ株式会社
Priority date: 2015-02-06
Filing date: 2016-02-04
Publication date: 2016-08-11
Also published as: JPWO2016125869A1

Abstract

The purpose of the present invention is to provide an inkjet ink for printing, inkjet printing method, fabric printed by an inkjet printing method, and inkjet printing system, with which it is possible to: improve the permeability to the reverse surface of a recording medium such as a fabric and the density on the surface of a recording medium such as a fabric, even in high-speed recording; improve the storage stability and discharge stability of an inkjet ink; and improve the drying performance of a recording medium such as a fabric. The aforementioned purpose is achieved by an inkjet ink containing polyalkylene glycol, a dispersed dye, and an anionic dispersing agent, the inkjet ink being characterized in that the weight-average molecular weight of the polyalkylene glycol is 400-1000.

Description

Inkjet ink, inkjet printing method, fabric printed by inkjet printing method, and inkjet printing system

The present invention relates to an inkjet ink, an inkjet printing method, a fabric printed by the inkjet printing method, and an inkjet printing system.

In recent years, in the field of textile printing, there has been a demand for a printing method corresponding to shortened delivery time and multi-product production. As an example, an ink-jet printing method that does not require plate making is known. Further, the ink-jet textile printing method can reduce the amount of ink used and the amount of waste discharged compared to the screen textile printing method that requires plate making. From this viewpoint, the use is expanding as an environmentally friendly technique. As a screen printing method, a method described in Patent Document 1 is known.

However, the inkjet printing method does not have a high recording speed as compared with the screen printing method, and there is a strong demand for a technique capable of forming an image at high speed even on a fabric having a certain area or more by the inkjet printing method.

As one of ink jet printing methods for solving such problems, a printing method using a multi-row head scanning method or an ink jet method using a one-pass method is known. In particular, the one-pass ink jet textile printing method can record one type or two or more types of ink on the surface of the recording medium by ejecting the ink jet head from the ink jet head in a single scan on the recording medium. Also, an image can be formed at a relatively high speed of 20 to 80 m / min.

In the textile printing method using inkjet ink, since a small amount of ink is used at the time of textile printing compared with the above-mentioned screen textile printing, it is important to have a technique that allows the dye to remain in the surface layer portion without penetrating the inside of the fabric fiber so as to have a high image density. is there. On the other hand, there is a case where a technique for increasing not only the fabric surface but also the back surface density to the same extent, such as a flag or a scarf, may be required.

JP 2007-224461 A

As a result of the inventor's investigation, it has become clear that new problems are manifested when ink-jet printing is attempted at a relatively high speed, such as the one-pass method. When an image is formed on a fabric at high speed by the inkjet method, post-processing such as drying of the fabric must be performed at high speed. For this reason, the ink permeability is not sufficient, and there may be a difference between the density of the fabric surface and the back surface.

On the other hand, when a highly permeable solvent or dye is used, the ink penetrates in the horizontal direction of the fabric, causing bleeding, or excessively penetrating the dye into the fabric, resulting in an increase in the back surface concentration. Therefore, it was also found that it is difficult to form a good image having the same density on the front and back surfaces. It has also been found that a highly penetrating solvent has a relatively high viscosity, which reduces ink ejection stability. The decrease in ejection stability is a particularly serious problem in the one-pass method in which it is difficult to eject ink due to the structure of the apparatus. In addition, since a high-speed ink jet printing apparatus such as the one-pass method is relatively expensive, it is also required from the viewpoint of improving productivity to make the maintenance interval as long as possible and to reduce downtime.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the permeability to the back surface of a recording medium such as a cloth and the density of the surface of the recording medium such as a cloth even in high-speed recording. Another object of the present invention is to provide an inkjet ink, an inkjet textile printing method, a fabric printed by the inkjet textile printing method, and an inkjet textile printing system that can improve ejection stability, ink storage stability, and drying properties.

As a result of intensive studies by the inventor, it was found that by containing polyalkylene glycol in the ink-jet ink, it is possible to form an image having good back surface permeability while suppressing bleeding. From the viewpoint of keeping the dye on the fabric surface, it has been found that it is effective to use a disperse dye dispersed with an anionic dispersant. An image having penetrability and high image density on the front and back surfaces could be formed.

That is, the object of the present invention can be achieved by the following configuration.

[1] An ink-jet ink containing a polyalkylene glycol and a disperse dye dispersed by an anionic dispersant, wherein the polyalkylene glycol has a weight average molecular weight of 400 or more and 1000 or less.

With the above configuration, it is possible to improve the permeability of the recording medium such as the fabric to the back surface and the density of the surface of the recording medium such as the fabric even in high-speed recording, and to improve the storage stability and ejection stability of the inkjet ink. And the drying property of a recording medium such as a fabric can be improved.

[2] The inkjet ink as described in [1], wherein the content of the polyalkylene glycol is 2% by mass or more and 10% by mass or less.

With the above configuration, even in high-speed recording, the permeability to the back surface of the recording medium such as cloth and the density of the surface of the recording medium such as cloth can be improved, and the storage stability and ejection stability of the ink-jet ink are good. And the drying property of a recording medium such as a fabric can be improved.

[3] The inkjet ink according to [1] or [2], wherein the inkjet ink contains ethylene glycol, and the content of the ethylene glycol is 25% by mass or more and 55% by mass or less. .

Therefore, with the above configuration, even in high-speed recording, the permeability to the back surface of a recording medium such as a cloth and the density of the surface of the recording medium such as a cloth can be improved, and the storability and ejection stability of the inkjet ink can be improved. Can be improved, and the drying property of a recording medium such as a fabric can be improved.

[4] An inkjet printing method, wherein a fabric is dyed by a one-pass method using the inkjet ink according to any one of [1] to [3].

[5] A fabric printed by the method described in [4].

[6] An inkjet printing system comprising the inkjet ink according to any one of [1] to [3] and an inkjet printing apparatus.
[7] The inkjet printing system according to [6], wherein the inkjet printing apparatus is a one-pass system.
[8] Dyeing a fabric containing a pretreatment agent having a pH lower than that of the anionic dispersant contained in the inkjet ink, using the inkjet ink according to any one of [1] to [3]. An ink-jet printing method characterized by the above.
[9] The ink-jet printing method according to [8], comprising a preliminary drying step after the image forming step.

According to the present invention, even in high-speed recording, the permeability to the back surface of a recording medium such as a cloth and the density of the surface of the recording medium such as a cloth can be improved, and the storability and ejection stability of inkjet ink can be improved. It is possible to provide an ink-jet ink for printing, an ink-jet printing method, a fabric printed by the ink-jet printing method, and an ink-jet printing system that can improve the drying property of a recording medium such as a fabric.

FIG. 1 is a diagram schematically illustrating an example of the configuration of an inkjet printing apparatus according to an embodiment of the present invention. FIG. 2A is a diagram schematically illustrating the configuration of the inkjet head unit according to the present embodiment when viewed in plan, and FIG. 2B is a diagram schematically illustrating the configuration of the inkjet head unit as viewed from the side. FIG. 2C is a diagram schematically illustrating the configuration of the inkjet head unit as viewed from the front.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the present invention, “˜” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value. In the present invention, “mass%” refers to the content of each component expressed in mass% when the total mass of the ink is 100 mass% unless otherwise specified.

1. Inkjet ink The inkjet ink according to the present invention contains at least a polyalkylene glycol, a disperse dye, and an anionic dispersant.

[Polyalkylene glycol]
The inkjet ink according to the present invention contains polyalkylene glycol from the viewpoint of allowing the disperse dye to smoothly penetrate into the back surface of a recording medium such as a fabric.

By incorporating a polyalkylene glycol having a relatively high boiling point into the ink-jet ink, the dye can penetrate into the back surface, and the back surface of a recording medium such as a fabric can be used even if the time for the image forming process is shortened by high-speed recording. The permeability to can be increased. Further, by setting the weight average molecular weight to 400 or more and 1000 or less, it is possible to improve ejection stability, ink storage stability, and drying properties. The reason why the polyalkylene glycol increases the permeability to the back side of the fabric is not clear in detail, but since the polyalkylene glycol has a higher boiling point than other organic solvents, in the preliminary drying step at the time of printing described below. It seems to be because it is relatively hard to volatilize. Therefore, it is considered that the polyalkylene glycol remaining in the fabric dissolves the disperse dye in the color developing step, so that the disperse dye easily penetrates into the fabric and the back surface permeability to the fabric is improved. On the other hand, it is considered that polyalkylene glycol having a relatively large molecular weight compared with other solvents has extremely low solubility of the disperse dye at room temperature and does not interact. Therefore, it is considered that the dye can be kept in a stable dispersed state and contributes not only to dispersion stability and ejection stability during storage, but also to suppression of bleeding when the ink lands on the fabric. In other solvents, organic solvents such as ethylene glycol having a relatively low molecular weight may volatilize in the preliminary drying step before the color forming step, and depending on the type of solvent, there may be high dye solubility even at room temperature. Therefore, it is assumed that such an effect does not appear.

Examples of the polyalkylene glycol that can be used in the present invention include polyethylene glycol and polypropylene glycol. These polyalkylene glycols can be used alone or in combination of two or more.

The weight average molecular weight of the polyalkylene glycol contained in the inkjet ink of the present invention is 400 or more and 1000 or less, preferably 400 or more and 800 or less. Use of a polyalkylene glycol having a weight average molecular weight exceeding the above-mentioned range is not preferable from the viewpoint of ink ejection stability, and is not suitable for high-speed ink because the drying load of the ink increases. Further, it is not preferable to use a polyalkylene glycol having a weight average molecular weight smaller than the above-mentioned range because the polyalkylene glycol volatilizes in the preliminary drying step or the color development step, and the back surface permeability is lowered. Since the solubility of alkylene glycol at room temperature is improved, the storage stability of ink and the suppression of bleeding are reduced.

The weight average molecular weight of the polyalkylene glycol can be measured by gel permeation chromatography (GPC).

Solvent: Tetrahydrofuran Column: Tosoh TSKgel G4000 + 2500 + 2000HXL
Column temperature: 40 ° C
Injection volume: 100 μl
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corp.) Weight average molecular weight = 1300000 to 500,000 calibration curves with 13 samples are used. Thirteen samples are used at approximately equal intervals.

The content of the polyalkylene glycol contained in the inkjet ink is preferably in the range of 2% by mass or more and 10% by mass or less with respect to the whole ink. More preferably, it is 3 mass% or more and 8 mass% or less. By setting the content of the polyalkylene glycol within the above range, the permeability to the back side of the fabric can be made moderate, and the discharge stability can be made good. Furthermore, by setting the polyalkylene glycol content within the above range, the disperse dye contained in the inkjet ink will not be excessively dissolved, so that the storage stability of the ink is improved and the volatility is also improved. Since it becomes moderate, the drying property of recording media, such as a cloth, becomes favorable.

[Disperse dye]
The ink-jet ink according to the present invention contains a disperse dye dispersed by an anionic dispersant described later.

There is no restriction | limiting in particular in the kind of dispersing agent, An appropriate dye can be selected in consideration of the desired use and color gamut.
Examples of disperse dyes include
C. I. Disperse Yellow: 3, 4, 5, 7, 9, 13, 23, 24, 30, 33, 34, 42, 44, 49, 50, 51, 54, 56, 58, 60, 63, 64, 66, 68 71, 74, 76, 79, 82, 83, 85, 86, 88, 90, 91, 93, 98, 99, 100, 104, 108, 114, 116, 118, 119, 122, 124, 126, 135 140, 141, 149, 160, 162, 163, 164, 165, 179, 180, 182, 183, 184, 186, 192, 198, 199, 202, 204, 210, 211, 215, 216, 218, 224 227, 231, 232,
C. I. Disperse Orange: 1, 3, 5, 7, 11, 13, 17, 20, 21, 25, 29, 30, 31, 32, 33, 37, 38, 42, 43, 44, 45, 46, 47, 48 49, 50, 53, 54, 55, 56, 57, 58, 59, 61, 66, 71, 73, 76, 78, 80, 89, 90, 91, 93, 96, 97, 119, 127, 130 139, 142,
C. I. Disperse Red: 1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 54, 55, 56, 58, 59, 60, 65, 72, 73 74, 75, 76, 78, 81, 82, 86, 88, 90, 91, 92, 93, 96, 103, 105, 106, 107, 108, 110, 111, 113, 117, 118, 121, 122 126, 127, 128, 131, 132, 134, 135, 137, 143, 145, 146, 151, 152, 153, 154, 157, 159, 164, 167, 169, 177, 179, 181, 183, 184 , 185, 188, 189, 190, 191, 192, 200, 201, 202, 203, 205, 206, 207, 210, 221, 224, 22 5, 227, 229, 239, 240, 257, 258, 277, 278, 279, 281, 288, 298, 302, 303, 310, 311, 312, 320, 324, 328, 337, 343
C. I. Disperse Violet: 1, 4, 8, 23, 26, 27, 28, 31, 33, 35, 36, 38, 40, 43, 46, 48, 50, 51, 52, 56, 57, 59, 61, 63 , 69, 77
C. I. Disperse Green: 9
C. I. Disperse Brown: 1, 2, 4, 9, 13, 19
C. I. Disperse Blue: 3, 7, 9, 14, 16, 19, 20, 26, 27, 35, 43, 44, 54, 55, 56, 58, 60, 62, 64, 71, 72, 73, 75, 77 79, 79: 1, 79: 2, 81, 82, 83, 87, 91, 93, 94, 95, 96, 102, 106, 108, 112, 113, 115, 118, 120, 122, 125, 128 , 130, 139, 141, 142, 143, 146, 148, 149, 153, 154, 158, 165, 167, 171, 173, 174, 176, 181, 183, 185, 186, 187, 189, 197, 198 , 200, 201, 205, 207, 211, 214, 224, 225, 257, 259, 267, 268, 270, 281, 284, 285, 287 288, 291, 291: 1, 293, 295, 297, 301, 315, 330, 333, 373
C. I. Disperse Black: 1, 3, 10, 24
Etc. are included. Among these, the disperse dye is C.I. in that the disperse stability of the disperse dye over time can be kept better. I. Disperse Blue 60 and C.I. I. It is preferable to include at least one of Disperse Red 343.

The content of the disperse dye is preferably 0.3% by mass or more and 20% by mass or less, and more preferably 0.5% by mass or more and less than 10% by mass with respect to the entire ink. By setting the content of the disperse dye within the above range, an ink having an appropriate balance between image density and ejection stability can be obtained.

It is preferable that the Z average particle size of the disperse dye is 300 nm or less, or the maximum particle size of the disperse dye is 900 nm or less. When the Z average particle size or the maximum particle size exceeds the above range, clogging is likely to occur in an ink jet printing method in which the fine nozzles emit light, and stable ink ejection may not be possible for a long time.

The Z average particle diameter or maximum particle diameter can be measured using a commercially available particle size measuring instrument using a light scattering method, electrophoresis method, laser Doppler method, etc., for example, Zetasizer Nano S manufactured by Malvern. is there. The Z average particle size or maximum particle size can be adjusted by dispersing the disperse dye with a bead mill using a commercially available dispersant, classification of the disperse dye, mixing of classified products, and the like.

[Anionic dispersant]
The ink-jet ink according to the present invention contains a disperse dye dispersed by an anionic dispersant described below.

As a result of further studies by the inventors, it has been found that when printing is performed with an ink-jet ink containing only polyalkylene glycol, the permeability to the back of the fabric becomes excessive, and the image density differs from the surface of the fabric. As a result of studying to improve the image density on the surface of the fabric while maintaining the permeability to the back side of the fabric, as a coloring material of the polyalkylene glycol-containing ink, a dispersed ink dispersed with an anionic dispersant is used. While maintaining good image density, the back surface permeability was moderate, and a preferred fabric having the same image density on the front and back surfaces of the fabric could be obtained.

明確 The clear reason for this is not clear, but is presumed as follows. The dye dispersed by the anionic dispersant has dispersion stability due to electrostatic interaction in the ink. In an inkjet printing method, it is common to apply a pretreatment agent before image formation with an ink containing a colorant. However, when a fabric dispersed with an anionic dispersant lands on a fabric having a pretreatment agent. The dispersion stability is lowered by a base component and acid-base reaction in the pretreatment agent or a pH change due to volatilization of the counter ion in the ink, and the dye is deposited on the upper part (surface) of the fabric. As a result, the disperse dye dispersed by the anionic dispersant has low penetrability into the fabric in the preliminary drying stage, and the dye remains on the fiber surface layer at the top of the fabric. In the subsequent color development step, the dye in the vicinity of the fiber penetrates into the upper fiber, and the dye relatively distant from the fiber diffuses while being dissolved in the polyalkylene glycol, and penetrates into the fiber in the lower part (back side) of the fabric. . For the reasons as described above, the configuration of the present invention can form images having good back surface permeability and high image density on the front and back surfaces. According to the printing method using the ink of the present invention, since the dependence due to dye penetration in the preliminary drying step is small, it can be particularly preferably used in the inkjet printing, particularly the printing method using the high-speed inkjet printing method.

The anionic dispersant that can be used in the present invention is a dispersant for facilitating dispersion of a water-insoluble disperse dye in water, and when dissolved in water, the hydrophilic group is ionized to exhibit an anionic property. Representative hydrophilic groups exhibiting anionic properties include a carboxyl group (—COOH), a sulfonic acid group (—SO ₃ H), a sulfate group (—OSO ₃ H), and the like.

As the anionic dispersant, a known polymer dispersant or the like can be used. Especially, it is preferable that dispersion resin is water-soluble resin, and it is more preferable to have a hydrophobic unit and a hydrophilic unit in good balance. The hydrophilic unit is anionic, and the anionic hydrophilic unit is preferably neutralized with a volatile base component.

Examples of such water-soluble resins include acrylic resins, polyvinyl alcohol resins, polyurethane resins, and polyester resins. The acrylic resin in the present invention is a resin having (meth) acrylic acid ester or (meth) acrylic acid as a monomer component; examples thereof include styrene-acrylic resin, acrylonitrile-acrylic resin, vinyl acetate- Acrylic resins are also included. Among these, a resin having a hydrophobic monomer unit and a hydrophilic monomer unit is preferable.

Examples of hydrophobic monomers include acrylic acid alkyl esters such as n-butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate (preferably C1-C12 alkyl esters of acrylic acid); ethyl methacrylate, methacrylic acid Methacrylic acid alkyl esters such as butyl and glycidyl methacrylate (preferably C1-C12 methacrylic acid alkyl esters); aromatic vinyl compounds such as styrene, α-methylstyrene and substituted styrene; α, β- such as acrylonitrile and methacrylonitrile Unsaturated nitriles; vinyl acetate, vinyl butyrate, vinyl benzoate and the like are included. Of these, acrylic acid alkyl esters, methacrylic acid alkyl esters and aromatic vinyl compounds are preferred.
One type of hydrophobic monomer may be used, or two or more types may be combined.

Examples of hydrophilic monomers include α, β-unsaturated acids such as acrylic acid and methacrylic acid; unsaturated group-containing dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid. Of these, α, β-unsaturated acids such as acrylic acid and methacrylic acid are preferred. One type of hydrophilic monomer may be used, or two or more types may be combined.

Specific examples of the resin having a hydrophobic monomer unit and a hydrophilic monomer unit include styrene-acrylic acid-alkyl acrylate copolymer, styrene-acrylic acid copolymer, styrene-maleic acid copolymer, styrene- Maleic acid-acrylic acid alkyl ester copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid half ester copolymer, vinylnaphthalene-acrylic acid copolymer Vinyl naphthalene-maleic acid copolymer and the like. Examples of commercially available products include JONCRYL series such as JONCRYL586 (manufactured by BASF), JONCRYL67 (manufactured by BASF), and JONCRYL819 (manufactured by BASF).

Among them, the resin having a hydrophobic monomer unit and a hydrophilic monomer unit is preferably a resin having at least an acrylic acid unit or a methacrylic acid unit as a hydrophilic monomer unit.

The acidic group derived from an acidic group-containing monomer such as acrylic acid or methacrylic acid in the anionic dispersant is preferably partially or completely neutralized with a base component. As the neutralizing base, alkali metal-containing bases (for example, sodium hydroxide, potassium hydroxide, etc.) and amines (for example, ammonia, alkanolamine, alkylamine, etc.) can be used. Among these, neutralization with amines having a boiling point of less than 200 ° C. is preferable from the viewpoint of improving image durability.

The acid value of the anionic dispersant is preferably 10 mgKOH / g or more and 300 mgKOH / g or less, more preferably 10 mgKOH / g or more and 150 mgKOH / g or less. By setting the acid value of the anionic dispersant within the above range, the dispersion stability in the ink and the affinity with the pigment can be improved.

The acid value of the anionic dispersant is the number of milligrams of potassium hydroxide (mgKOH / g) required to neutralize the acidic component contained in 1 g of the anionic dispersant; it can be measured by measuring the acid value according to JISK0070. it can.

The acid value according to JIS K0070 can be measured by the following method. That is, 10 g of resin is weighed into a 300 ml Erlenmeyer flask, and about 50 ml of a mixed solvent of ethanol: benzene = 1: 2 is added to dissolve the resin. Subsequently, this solution is titrated with a 0.1 mol / L potassium hydroxide ethanol solution standardized in advance using a phenolphthalein indicator. And the acid value (mgKOH / g) is calculated | required by the following formula (1) from the quantity of the potassium hydroxide ethanol solution used for titration.
If the resin does not dissolve in about 50 ml of a mixed solvent of ethanol: benzene = 1: 2, the same titration is performed using either 50 ml of ethanol or about 50 ml of a mixed solvent of ethanol / pure water = 1: 1. I do.

Formula (1)
A = (B × f × 5.611) / S
(In the formula, A is the acid value of the resin (mgKOH / g), B is the amount (ml) of 0.1 mol / L potassium hydroxide ethanol solution used for titration, and f is 0.1 mol / liter potassium hydroxide ethanol solution. Factor, S is the mass of resin (g), 5.611 is 1/10 of the formula weight of potassium hydroxide (56.11 / 10))

The weight average molecular weight of the anionic dispersant is preferably 3000 to 30000, and more preferably 7000 to 20000 from the viewpoints of ink dispersion stability, ejection stability, and ease of handling.

The glass transition temperature (Tg) of the anionic dispersant is preferably −30 ° C. to 100 ° C., and more preferably −20 ° C. to 80 ° C.

Specific examples of the anionic dispersant include Jonkrill 67, 586, and 819 (above, water-soluble polymer compound manufactured by BASF).

The content of the anionic dispersant is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 6% by mass or less with respect to the whole ink.
The mass ratio of the disperse dye to the anionic dispersant is preferably from 100/150 to 100/15, more preferably from 100/100 to 100/20 for the disperse dye / anion dispersant. By being within the above range, it is possible to have good dispersion stability and ejection stability.

[Water-soluble organic solvent]
The ink of the present invention may contain a water-soluble solvent.
Inkjet images are formed by ejecting minute droplets from minute head nozzles, but inkjet nozzles do not always eject ink. When the solvent in the solvent evaporates to increase the viscosity or the solid component precipitates, the ejection becomes unstable or nozzle clogging occurs.
Discharge instability and nozzle clogging have a great influence on image formation by inkjet. In particular, unlike the scanning method, the influence is particularly great in the one-pass method in which the head does not move left and right. Therefore, it is water-soluble from the viewpoint of suppressing ink volatility, maintaining high moisture retention, or making ink physical properties such as viscosity and solubility difficult to change even when part of the ink solvent volatilizes, and maintaining ejection stability. The type and amount of organic solvent can be selected.

Examples of water-soluble organic solvents that can be used in the present invention include
Alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, etc.);
Polyhydric alcohols (eg, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.);
Amines (eg, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyl Diethylenetriamine, tetramethylpropylenediamine, etc.);
Amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.);
Heterocycles (eg 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone);
Sulfoxides (eg, dimethyl sulfoxide, etc.);
Glycol ethers (for example, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether) , Dipropylene glycol monopropyl ether, tripropylene glycol monomethyl ether, etc.);
1,2-alkanediols (for example, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, etc.)
Etc. These may be used alone or in combination of two or more.

The content of the water-soluble organic solvent is preferably 10% by mass or more based on the whole ink from the viewpoint of improving the ejection stability, and maintaining the storage stability and dispersion stability of the dye due to excessive water-soluble organic solvent, and From the viewpoint of suppressing excessive back surface permeability, it is preferably less than 60% by mass. A more preferable range is 20% by mass or more and less than 45% by mass.

Among these, the water-soluble organic solvent preferably contains a polyhydric alcohol from the viewpoint of improving ejection stability, and more preferably contains ethylene glycol. From the same viewpoint as the content of the water-soluble organic solvent, the content of ethylene glycol is preferably 25% by mass or more and 55% by mass or less, and preferably 30% by mass or more and 45% by mass or less with respect to the entire ink. More preferably.

[Other ingredients]
The ink-jet ink according to the present invention may further contain a surfactant, an antiseptic agent, an antifungal agent and the like as necessary.

Examples of surfactants include dialkyl sulfosuccinates, alkyl naphthalene sulfonates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, alkyls Examples include amine salts, quaternary ammonium salts, silicone surfactants other than the compounds represented by formula (1) or (2), or fluorine surfactants. The content of the surfactant is preferably adjusted so that the surface tension of the ink is 25 to 60 mN / m. Specifically, it may be about 0.0001 to 5% by mass with respect to the whole ink.

Examples of preservatives or antifungal agents include aromatic halogen compounds (eg, Preventol® CMK), methylene dithiocyanate, halogen-containing nitrogen sulfur compounds, 1,2-benzisothiazolin-3-one (eg, PROXELGXL) and the like. included.

[Physical properties of inkjet ink]
The viscosity at 25 ° C. of the inkjet ink according to the present invention is preferably 1 to 40 mPa · s, more preferably 5 to 40 mPa · s, from the viewpoint of obtaining ink ejection stability, and 5 to 20 mPa · s. More preferably, it is s. The viscosity of the ink can be measured with an E-type viscometer at 25 ° C. and 1 rpm.
Further, the surface tension of the ink at 25 ° C. is preferably 25 to 60 mN / m. The pH of the ink is not particularly limited, but is preferably 6 or more, more preferably in the range of 7-9. From the viewpoint of improving the surface concentration, it is preferable to lower the pH of the pretreatment agent than the pH of the ink.

The inkjet ink according to the present invention can be manufactured by an arbitrary method, for example, through a process of obtaining a dispersion by dispersing a disperse dye with a dispersant and a process of preparing an ink using the dispersion.

2. Inkjet Textile Printing Method In general, when a fabric is used as the recording medium, the inkjet textile printing method includes (1) a step (pretreatment step) of applying a pretreatment agent to the fabric in order to prevent ink bleeding. 2) a step of ejecting ink-jet ink droplets onto the fabric to which the pretreatment agent has been applied and soaking the ink (image forming step); and (3) a step of pre-drying the ink-jet ink droplets that have landed on the fabric ( A preliminary drying step) and (4) a step of fixing the dye of the ink-jet ink landed on the fabric to the fiber (coloring step). Further, it may include (5) a step of removing dyes and pretreatment agents that could not be fixed to the fabric (washing step), and (6) a step of drying the washed fabric (drying step) as necessary. .

An inkjet textile printing method according to the present invention includes a step of ejecting at least a droplet of the inkjet ink according to the present invention from the recording head and depositing the droplet on the recording medium, and a step of recording the droplet deposited on the recording medium. Fixing to a medium.

The recording medium has a property of absorbing an aqueous medium (absorbability of the aqueous medium). Absorptivity refers to the property that an aqueous medium adhering to a recording medium penetrates into the recording medium while spreading both in the direction along the surface of the recording medium and in the thickness direction of the recording medium. The aqueous medium in which the recording medium exhibits absorbency may be the same as or different from the aqueous medium in the ink.

The recording medium can be selected from recording media that have absorbency and can be used in textile printing. The recording medium may be, for example, a sheet or a model formed of fibers, and the material of the fibers is appropriately selected as long as the effect of the present embodiment is obtained. The recording medium is, for example, a fabric.

The fabric is composed of fibers that can be dyed with disperse dyes. Examples of such fabrics are applicable to fibers that can be dyed with disperse dyes. Specifically, polyester fibers such as polyethylene terephthalate, cationic dyeable polyester fibers, acetate fibers, diacetate fibers, triacetate fibers, Examples include polylactic acid fibers. The thickness of the fibers constituting the fabric is preferably 10 to 100d. Also, the thickness of the fabric is not particularly limited, but is preferably 3 mm or less and more preferably 1 mm or less from the viewpoint of fabric strength and back surface permeability.

[Pretreatment process]
The pretreatment step is a step of treating the fabric with a pretreatment agent in advance in order to prevent ink bleeding on the fabric and obtain a clear image. The pretreatment method is not particularly limited, and a method suitable for the material and ink of the fabric can be appropriately selected from conventionally known methods. For example, a method of applying a pretreatment agent to a fabric by a pad method, a coating method, a spray method or the like can be mentioned. The applied amount (squeezing ratio) of the pretreatment agent may be, for example, 0.2% by mass to 90% by mass with respect to the total mass of the fabric, although it depends on the type of fabric and its application.

The pretreatment agent contains at least one selected from a water-soluble polymer, a water-soluble metal salt, a polycation compound, a surfactant, a water repellent, and a pH adjuster, preferably a water-soluble polymer.

The water-soluble polymer can be a natural water-soluble polymer or a synthetic water-soluble polymer. Examples of natural water-soluble polymers include starches such as corn and wheat, cellulose derivatives such as carboxymethylcellulose, methylcellulose and hydroxyethylcellulose; polysaccharides such as sodium alginate, guar gum, tamarind gum, locust bean gum and gum arabic; Protein substances such as gelatin, casein and keratin are included. Examples of the synthetic water-soluble polymer include polyvinyl alcohol, polyvinyl pyrrolidone, acrylic acid polymer and the like.

Examples of water-soluble metal salts include inorganic salts or organic acid salts such as alkali metals or alkaline earth metals. Examples of the polycation compound include polymers or oligomers of various quaternary ammonium salts, polyamine salts, and the like. Among water-soluble metal salts and polycation compounds, there are those that change the color tone of the fabric or reduce the light fastness, and therefore it is preferable to select them according to the type of the fabric.

Examples of the surfactant include anionic, cationic, amphoteric and nonionic ones. Examples of anionic surfactants include higher alcohol sulfates and sulfonates of naphthalene derivatives; examples of cationic surfactants include quaternary ammonium salts; amphoteric surfactants Examples of the agent include imidazoline derivatives and the like; examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and acetylene alcohol. Ethylene oxide adducts and the like are included.

Examples of water repellents include silicon water repellents, fluorine water repellents, and wax water repellents.

These water-soluble polymers and surfactants are preferably stable even in a high-temperature environment so as not to cause tarring or other stains when coloring at high temperature after image formation. In addition, the water-soluble polymer and the surfactant are preferably those that can be easily removed from the fabric by a cleaning treatment after color formation at a high temperature after image formation.

It is preferable that the pretreatment agent further includes a pH adjusting agent. The pH adjuster is preferably an acid, and specific examples thereof include citric acid, malic acid, tartaric acid and the like. By adding an acid as a pH adjuster to the pretreatment agent, a clear image can be formed at a higher density. The pH of the pretreatment agent is not particularly limited, but the effect of the present invention can be better exhibited by using a pH lower than the pH of the ink.

The pretreatment agent may further contain optional components such as a reduction inhibitor, a chelating agent, a preservative, and a softening agent as necessary. Examples of the reducing agent include sodium m-nitrobenzenesulfonate. Examples of chelating agents include aminopolycarboxylates, hydroxycarboxylates, polycarboxylates, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid, diethylenetriaminepentaacetic acid, and the like. The preservative may be the same as the preservative exemplified for the ink, or may be the same.

[Image formation process]
The image forming step is a step of forming a pre-colored image by discharging droplets of the inkjet ink according to the present invention from the inkjet recording head toward the fabric. Ink droplets are ejected and landed on the fabric while moving the fabric relative to a head carriage on which a plurality of inkjet recording heads are mounted. The ink droplets for each color may be ejected separately or simultaneously. From the standpoint of suppressing bleeding of the pre-colored image, the fabric may be heated as necessary when forming the image.

[Pre-drying process]
The preliminary drying step is a step of preliminary drying ink jet ink droplets that have landed on a recording medium such as a fabric. After the image forming process and the preliminary drying process, it is wound up, stored, transported, and may be a coloring process and a washing process in another machine. Therefore, preliminary drying is performed so as not to cause color transfer during winding. In the preliminary drying step, for example, drying is performed at 110 ° C. to 130 ° C. for 2 minutes.

[Color development process]
The color development step is a step in which a dye in an image before a color development reaction that is not sufficiently dyed in the fabric is dyed on the fabric to develop the original hue of the ink. The method may be a conventionally known method, for example, a steaming method, an HT steaming method, an HP steaming method, a thermofix method, an alkali pad steam method, an alkali blotch steam method, an alkali shock method, or an alkali cold fix method. Etc., and is appropriately selected depending on the ink or the fabric. For example, the polyester fiber is preferably treated at 160 to 180 ° C. for 5 to 10 minutes when subjected to high temperature steam with an HT steamer; about 30 at 130 to 140 ° C. when subjected to high pressure steam with an HP steamer. It is preferable that the treatment is performed for a minute. In addition, the fabric on which the image before the color development reaction is formed may be colored immediately or may be colored after a lapse of time.

[Washing process]
The washing step is a step of removing dyes and pretreatment agents that could not be dyed on the fabric after the color development step of the fabric. As the cleaning method, a conventionally known water-washing method, soaping method, or the like can be used, and is appropriately selected depending on the type of the ink-jet ink or fabric. For example, a cloth mainly composed of polyester fibers can be generally washed with a mixed solution of caustic soda, a surfactant and hydrosulfite.

[Drying process]
The drying process is a process performed after the washing process and drying the washed fabric. Although the drying method is not particularly limited, the washed fabric is squeezed, dried, or dried using a dryer (heat roll, iron, etc.).

[Fabric]
The fabric printed by the above-described method has less bleeding and forms an image having good back surface permeability.

[Inkjet printing equipment]
Hereinafter, an inkjet printing apparatus will be described with reference to the drawings. However, the inkjet printing apparatus used in the inkjet printing method according to the present invention is not limited to this.

The ink-jet printing method of the present embodiment can also be performed by, for example, a known one-pass ink-jet printing apparatus provided with a humidifier. FIG. 1 is a diagram schematically showing an example of the configuration of the ink jet textile printing apparatus according to the present embodiment. As shown in FIG. 1, the inkjet textile printing apparatus 10 includes four inkjet head units 11 corresponding to yellow, magenta, cyan, and black colors, and a conveyor belt for continuously supplying a fabric 100 as a recording medium. And having. An arrow X in FIG. 1 indicates the conveyance direction of the fabric 100.

FIG. 2A is a diagram schematically illustrating the configuration of the inkjet head unit 11 when viewed in plan, and FIG. 2B is a diagram schematically illustrating the configuration of the inkjet head unit 11 as viewed from the side. FIG. 2C is a diagram schematically illustrating the configuration of the inkjet head unit 11 when viewed from the front. As shown in FIGS. 2A to 2C, each of the inkjet head units 11 includes a plurality of inkjet heads 111 arranged in two rows along the width direction of the fabric indicated by the arrow Y, and humidified air to the fabric 100. And a blowout port 112 for blowing out. All of the inkjet head units 111 are fixed on the transport belt.

The inkjet heads 111 are arranged so as to partially overlap each other in the Y direction, and are arranged without any gaps as a whole. The outlet 112 is a duct having an elongated rectangular opening that extends from the center in the Y direction along the Y direction, and corresponds to a humidifier. The outlet 112 is disposed upstream of the inkjet head 111 in the X direction and extends to a range at least overlapping with all the inkjet heads 111 in the Y direction. The inkjet head 111 has, for example, an ink chamber (not shown), a pressure chamber, and a nozzle, and is connected to an ink tank that stores ink of each color. The outlet 112 is connected to a humidifier (not shown), for example.

As shown in FIG. 1, the conveyor belt is arranged at an endless adhesive belt 21, a support roll 22 and a conveyor roll 23 that support the adhesive belt 21, and a position between the conveyor roll 23 and the adhesive belt 21. Nip roll 24. The adhesive belt 21 has adhesiveness on the surface on which the fabric 100 is placed. The conveyance roll 23 is configured to be driven to rotate freely, and the support roll 22 is arranged to be rotatable. Further, the nip roll 24 is disposed so as to be able to approach and separate from the transport roll 23.

When the conveying belt is driven, the fabric 100 is continuously conveyed in the X direction. The fabric 100 is pre-treated by applying a pre-treatment liquid and drying it.

Next, the fabric 100 is supplied with humidified air of, for example, 25 ° C. and 70 RH% at 2 m / s from the outlet 112 of the inkjet head unit 11 on the upstream side. By supplying humidified air, the surface of the fabric 100 is moistened to the same extent as when ink droplets land. Then, the first ink is ejected from the inkjet head 111 to the wetted portion of the fabric 100. Similar humidification and second and subsequent ink ejections are also performed in the inkjet head 111 on the downstream side.

In this way, the ink of the desired color is ejected to the fabric 100 only once through the inkjet head unit 11, and a desired image is formed on the surface of the fabric 100. The fabric 100 on which an image is formed as described above is subjected to the above-described preliminary drying, coloring, washing, and drying steps.

The transport speed of the recording medium is not particularly limited, but is preferably 20 to 80 m / min from the viewpoint of high speed recording.

[Inkjet printing system]
The above-described inkjet ink may be loaded into the above-described inkjet printing apparatus to form an inkjet printing system.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

[Preparation of ink]
(Dissolution of the dispersant)
Dissolve 1.2% by weight of sodium hydroxide in 78.8% by weight of ion-exchanged water, and add 20% by weight of Joncryl 819 (styrene-acrylic copolymer BASF) as an anionic dispersant. Dissolved by heating and stirring.

(Preparation of disperse dye solution)
15% by mass of the dispersant aqueous solution was added to and mixed with a mixture of 45% by mass of ion-exchanged water and 20% by mass of ethylene glycol. In this solution, the disperse dye C.I. I. Disperse Blue 60 was added in an amount of 20% by mass, premixed, and then dispersed using a sand grinder filled with 50% by volume of 0.5 mm zirconia beads to obtain a dispersed dye solution having a dye solid content of 20% by mass.
It was 0.15 micrometer when the Z average particle diameter of the dispersed particle of the obtained disperse dye liquid was measured with the dynamic light-scattering-method particle size distribution analyzer Zetasizer nano S (made by Malvern).

(Adjustment of ink No. 1)
27.6% by mass of ion-exchanged water, 35% by mass of ethylene glycol, 7% by mass of glycerin, 0.2% by mass of proxel GXL (an antifungal agent, Lonza), 5% by mass of polyethylene glycol having a weight average molecular weight of 600 In addition, 25% by mass of the disperse dye solution was added to a mixed solution in which 0.2% by mass of KF-351A (surfactant Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was stirred and then filtered through a 1 μm filter. Is 100 parts by mass. 1 was obtained.

Similarly, according to the composition of the ink described in Table 1 below, the following components and the disperse dye liquid were added to adjust the ink. Inks of 2 to 9 were obtained. In addition,% shown as a unit of each component of Table 1 is the mass%.

(Disperse dye)
DY114: C.I. I. Disperse YELLOW 114
DB60: C.I. I. Disperse BLUE 60
(Dispersant)
J 819: Jonkrill 819 (manufactured by BASF) (anionic dispersant)
C 3000: Jonkrill JDX-C 3000 (manufactured by BASF) (anionic dispersant)
BYK190: DISPER BYK190 (manufactured by Big Chemie Japan) (nonionic dispersant)
(Polyalkylene glycol)
PEG200: Polyethylene glycol (manufactured by Kanto Chemical Co.) (weight average molecular weight 200)
PEG400: Polyethylene glycol (manufactured by Kanto Chemical Co., Inc.) (weight average molecular weight 400)
PEG600: Polyethylene glycol (manufactured by Kanto Chemical Co.) (weight average molecular weight 600)
PEG1000: Polyethylene glycol (manufactured by Kanto Chemical Co.) (weight average molecular weight 1000)
PEG2000: Polyethylene glycol (manufactured by Kanto Chemical Co.) (weight average molecular weight 2000)
PPG400: Polypropylene glycol (manufactured by Kanto Chemical Co.) (weight average molecular weight 400)
(Water-soluble organic solvent)
EG: Ethylene glycol (Kanto Chemical Co., Inc.)
GLY: Glycerin (manufactured by Kanto Chemical Co., Inc.)
(Antidepressant)
Proxel GXL (Lonza)
(Surfactant)
KF-351A (manufactured by Shin-Etsu Chemical Co., Ltd.)

[Inkjet printing method]
A polyester fabric having a thread thickness of 50d is pre-treated soaked in a carboxymethylcellulose aqueous solution, squeezed and dried, and prepared using a one-pass tester, using each ink prepared above, 100 mm × 100 mm After printing on the fabric and pre-drying at 120 ° C. for 2 minutes, treated by the HT steaming method at 175 ° C. for 10 minutes, washed with water, and at 80 ° C. with a 0.2% hydrosulfite aqueous solution. Reduction cleaning was performed, followed by thorough washing with water and drying.

The conveyance speed of the fabric as the recording medium was 20 m / min.

[Image evaluation]
Each ink (Nos. 1 to 9) produced above was evaluated as follows.

(Front / back surface density)
The density of the front and back surfaces of the printed part was visually evaluated.
◎: Concentration is sufficiently high ○: Concentration is high and no problem △: Concentration is slightly low, but practical use ×: Concentration is low and impractical

(Discharge stability)
The faintness and missing prints of the printed part when a rectangle was continuously printed 100 m every 500 mm were visually evaluated.
◎: No fading or missing prints ○: Slight fading is observed, but no problem △: Fading is observed, and printed missing parts are often seen, but the image is not disturbed and can be used practically ×: Fading Image is distorted due to lack of printing, impractical

(Drying)
After the preliminary drying, the printed part was rubbed with the back surface of the unprinted cloth, and the color transfer was visually evaluated.
A: No color transfer
○: If you look closely, there is a slight color shift, but you are not interested at all △: There is a slight color shift, but it is practical
×: Severe color transfer, impractical

(Ink storage stability)
The ink was stored at 50 ° C. for 1 week, and the change in the average particle diameter before and after storage was evaluated.
A: Variation in particle size is less than ± 5 nm B: 5 nm or more and less than 15 nm Δ: 15 nm or more and less than 30 nm, but practical use ×: 30 nm or more, impractical

Evaluation results are shown in Table 1.

According to the present invention, the inkjet ink for printing, the inkjet printing method, and the inkjet printing that can improve the permeability to the back surface of the recording medium such as the fabric and the density of the surface of the recording medium such as the fabric even in the high-speed recording. Fabrics printed by the method and inkjet printing systems can be provided.

This application claims priority based on Japanese Patent Application No. 2015-022458 filed on February 6, 2015, and the contents described in the claims, specification and drawings of this application are Incorporated into the application.

DESCRIPTION OF SYMBOLS 10 Inkjet printing apparatus 11 Inkjet head unit 21 Adhesive belt 22 Support roll 23 Conveyance roll 24 Nip roll 111 Inkjet head 112 Outlet X Arrow which shows the conveyance direction of a cloth Y Arrow which shows the width direction of a cloth

Claims

An inkjet ink comprising a polyalkylene glycol, a disperse dye and an anionic dispersant, wherein the polyalkylene glycol has a weight average molecular weight of 400 or more and 1000 or less.
The ink-jet ink according to claim 1, wherein the content of the polyalkylene glycol is 2% by mass or more and 10% by mass or less.
The inkjet ink according to claim 1 or 2, wherein the inkjet ink contains ethylene glycol, and the content of the ethylene glycol is 25 mass% or more and 55 mass% or less.
An inkjet printing method comprising dyeing a fabric by a one-pass method using the inkjet ink according to any one of claims 1 to 3.
A fabric printed by the method according to claim 4.
An inkjet printing system comprising the inkjet ink according to any one of claims 1 to 3 and an inkjet printing apparatus.
The inkjet printing system according to claim 6, wherein the inkjet printing apparatus is a one-pass system. *
A fabric containing a pretreatment agent having a pH lower than that of the anionic dispersant contained in the inkjet ink is dyed using the inkjet ink according to any one of claims 1 to 3. Inkjet printing method.
9. An ink jet printing method according to claim 8, further comprising a preliminary drying step after the image forming step.