KR20220153748A - A capsulated pigment dispersion and method for preparing the same - Google Patents

Abstract

The present invention relates to an encapsulated pigment dispersion and a manufacturing method thereof and, specifically, to a manufacturing method of the encapsulated pigment dispersion, which comprises the steps of: mixing encapsulated pigment dispersion containing (a) organic pigments (b) a polymeric dispersant (c) a crosslinking agent and (d) water, organic pigment, a polymer dispersing agent and water; dispersing the organic pigment using a bead mill; and performing reaction by adding a crosslinking agent. The encapsulated pigment dispersion according to the present invention, particularly, is useful for inkjet inks.

Description

Encapsulated pigment dispersion and its manufacturing method {A CAPSULATED PIGMENT DISPERSION AND METHOD FOR PREPARING THE SAME}

The present invention relates to an encapsulated pigment dispersion comprising an encapsulated organic pigment dispersed in an aqueous liquid medium and a process for its preparation. Specifically, the present invention relates to (a) an organic pigment; (b) a polymeric dispersant; (c) a crosslinking agent, and (d) an encapsulating pigment dispersion comprising water, and the use of said dispersion in inks, especially inkjet printing inks.

Conventionally, inks used in the inkjet recording system have been mainly those in which various water-soluble dyes are dissolved in water alone or in a solvent composed of water and a water-soluble solvent, and various additives are added as necessary. However, in the case of printing using such a dye-based ink, there is a problem that dye bleeding occurs due to low water resistance of a recorded image on a recording medium, or color tone change or density decrease due to light due to low light resistance.

In order to improve the above problems of dye-based inks, it is known to apply so-called pigment-based inks using carbon black or various organic pigments as colorants to an inkjet recording method. In the case of printing using pigment-based ink, the dry ink on the recording medium does not dissolve in water or smear, and thus has good water resistance. In addition, since pigments have lower reactivity to light than dyes, the light resistance of pigment-based inks is superior to that of dye-based inks.

These pigment-based inks are generally prepared by adding various additives to a pigment dispersion prepared by dispersing a mixture composed of a pigment, a liquid medium, and a dispersant with a ball mill, sand mill, or the like. The pigment dispersion used in ink for inkjet recording is usually composed of pigment particles in the pigment dispersion to a particle diameter level of 200 nm or less in order to prevent nozzle clogging of the printing device (inkjet printer), to ensure the clarity of printed images, secondary color reproducibility, and transparency. It needs to be atomized and dispersed. In addition, it is known that an image with high chroma and high transparency close to that of dye ink can be formed when micronized to a particle diameter level of 50 nm or less.

Pigment dispersions of pigment particles used in inkjet ink are produced in various ways using polymer dispersions, self-dispersion solutions, encapsulating dispersions, and the like.

In addition to cyan, magenta, yellow, and black used as the basic four colors of inkjet pigment ink, orange, green, red, blue, violet, and fluorescent inks can be used as spot color inks to broaden the color range.

Recently, many pigment inks and latex inks for DTP printing on textiles have been developed, and higher quality (physical properties, stability over time, and solvent resistance) than pigment dispersions used in existing water-based pigment inks are required.

In particular, in order to be applied to DTP printing using an inkjet head, which discharges liquid droplets through a nozzle of tens of microns, the stability of the ink composition must be secured to ensure productivity through long-term ejection capability.

The pigment can be uniformly dispersed in a medium using a dispersant, but if the combination of the pigment and the dispersant is not correct, particle aggregation is caused and the stability of the dispersion is destroyed. In addition, the water-soluble organic solvent used in the ink composition causes particle aggregation by causing separation of the dispersant as the amount used increases (see Patent Documents 1 to 4).

Therefore, the present inventors have developed a formaldehyde-free aqueous pigment dispersion having suitable physical properties (small particle size, low viscosity, excellent filterability, etc.) that can solve the above-mentioned problems, and excellent dispersion stability and mixing stability with ink composition materials. By inventing, it is intended to provide an encapsulated pigment dispersion useful for inkjet inks, especially pigment inks and latex inks for DTP.

In addition, it is intended to provide the encapsulated pigment dispersion according to the present invention as a colorant useful for eco-friendly inks, paints, coatings, textiles, and stationery.

KR 2009-0065209 A US 2013-0065996 A US 8591021 B JP 2013-538275 A

An object of the present invention is (a) an organic pigment; (b) a polymeric dispersant; (c) a crosslinking agent, and (d) water.

Another object of the present invention is to provide a method for preparing an encapsulated pigment dispersion useful for ink, particularly inkjet ink, by dispersing an organic pigment with a polymer dispersant and encapsulating it with a crosslinking agent.

In order to achieve the above object, the present invention is (a) an organic pigment; (b) a polymeric dispersant; (c) a crosslinking agent, and (d) water.

The present invention also provides a method for preparing an encapsulated pigment dispersion useful for ink, particularly ink for inkjet, by dispersing an organic pigment with a polymeric dispersant and encapsulating it with a crosslinking agent.

In order to impart high chroma and excellent storage stability, the encapsulated pigment dispersion according to the present invention is mixed with a pigment, a polymer dispersant and water, dispersed in a bead mill, and encapsulated with a crosslinking agent to have a small particle size and excellent filterability. It provides an encapsulated pigment dispersion having particularly excellent mixing stability with ink composition materials, and can be used as a colorant in ink, especially inkjet ink.

In addition, the encapsulated pigment dispersion according to the present invention can be used for eco-friendly paints, textiles, stationery, etc. that are harmless to the human body and the environment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is one well known and commonly used in the art.

In one aspect, the present invention provides (a) an organic pigment; (b) a polymeric dispersant; (c) a cross-linking agent; and (d) water.

In another aspect, the present invention is to provide a method for preparing an encapsulated pigment dispersion useful for ink, particularly ink for inkjet, by dispersing organic pigments with a polymer dispersant and encapsulating them with a crosslinking agent.

In the present invention, the organic pigment may be azo-based, phthalocyanine-based, condensed polycyclic, quinacridone-based, nitro-based and nitroso-based, black-based colorants such as carbon black, lamp black, acetylene black, and channel black. .

Since the diameter of the inkjet head is as small as several microns, it is required that the particle size of the organic pigment be very small, especially in the case of inkjet pigment ink.

The average particle diameter of the organic pigment is preferably 50 nm to 200 nm, and more preferably 70 nm to 150 nm. If the average particle diameter is less than 50 nm, the chromaticity of the image decreases, and if it exceeds 200 nm, ink ejection stability may deteriorate. Therefore, by setting the average particle diameter of the organic pigment to 70 nm to 150 nm, irregular reflection of the pigment particles can be prevented and a printed image having a uniform density can be provided.

In the present invention, the polymer dispersant is styrene, chlorostyrene, vinyltoluene, 2-ethylhexyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, benzyl ( meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate , tetrahydrofurryl (meth)acrylate, hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-chloro Propyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, diethylamino (meth)acrylate, ethylhexylacrylate, 2-methoxyethyl (metha)acrylate )Acrylate, 3-methoxybutyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxytripropylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, p-nonylphenoxypolyethylene glycol (meth)acrylate, p-nonylphenoxypolypropylene glycol (meth)acrylate Acrylate, tetrafluoropropyl (meth)acrylate, 1,1,1,3,3,3-hexafluoroisopropyl (meth)acrylate, methyl α-hydroxymethyl acrylate, ethyl α-hydroxy The group consisting of methyl acrylate, propyl α-hydroxymethyl acrylate, butyl α-hydroxymethyl acrylate, N-phenylmaleimide, N-(4-chlorophenyl)maleimide, methacrylic acid, maleic acid, and itaconic acid It may be characterized in that it is prepared by polymerizing one or more selected from.

In the present invention, the encapsulated pigment dispersion contains 10 to 50% by mass of an organic pigment, 5 to 25% by mass of a polymer dispersant, 1 to 10% of a crosslinking agent, and 15 to 84% by mass of water, based on 100% by mass of the total dispersion composition. It can be characterized by doing.

In the present invention, the encapsulated pigment dispersion is useful for ink, particularly inkjet ink, and may be characterized as a colorant for paints, coatings, textiles, or stationery.

In the present invention, the encapsulated pigment dispersion may be characterized by having a viscosity of 2 to 20cps, 3 to 15cps, or 4 to 10cps.

In the present invention, the encapsulated pigment dispersion has a filterability of 20 to 500g, 100 to 500g, or 250 to 500g based on a syringe filter having a filter pore size of 0.8 μm. can be characterized.

In the present invention, the method for preparing the encapsulated pigment dispersion includes (a) adding and mixing an organic pigment, a polymer dispersant, and water, (b) dispersing at a temperature of 15 to 40 ° C. or 20 to 40 ° C. with a bead mill preparing a pigment dispersion; and (c) a crosslinking agent to prepare an encapsulated pigment dispersion.

When the temperature in the dispersion step is less than 15 ° C, the water solubility of the dispersant adsorbed on the surface of the organic pigment may deteriorate or the viscosity may increase. Desorption may occur, resulting in a decrease in dispersibility and a decrease in stability of the dispersion.

In addition, the pigment dispersion may be characterized by preparing an encapsulated pigment dispersion by adding a crosslinking agent in the crosslinking agent reaction step and then reacting at a temperature of 30 to 80 ° C. At a temperature below 30 ° C, the reactivity is low, and the effect of encapsulation is low even when reacted for a long time. It is not preferable because there is a problem that the particle size increases during the encapsulation reaction. In one embodiment, when the crosslinking agent included in the pigment dispersion according to the present invention is a water-soluble epoxy crosslinking agent, in the method for preparing the pigment dispersion, after adding the crosslinking agent, at a temperature of 50 to 75 ℃, 4 to 12 hours It is characterized by preparing an encapsulated pigment dispersion by reacting during.

As used herein, the term "composition" is considered to include not only products containing specific components, but also any products made directly or indirectly by combining specific components.

Hereinafter, the components and manufacturing method of the encapsulated pigment dispersion of the present invention will be described in detail.

organic pigment

Examples of the organic pigment used in the present invention include coloring agents such as azo, phthalocyanine, condensed polycyclic, quinacridone, nitro and nitroso, black-based carbon black, lamp black, acetylene black, and channel black. .

Examples of magenta pigments include C. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22 , 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168, 170, 171, 175, 176, 178, 179, 184, 185, 187, 202, 209, 219, 245, C. I. Pigment Violet 19, 23, 32, 33, 36, 38, 43, 50, etc.

Examples of the yellow pigment include C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55 , 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147 , 151, 153, 154, 167, 172, 180, etc.

Examples of cyan pigments include C. I. Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:34, 15:4, 16, 18, 22, 25, 60, 65 , 66, etc.

Other pigments other than magenta, yellow, and cyan include, for example, C. I. Pigment Green 7, 10, C. I. Pigment Brown 3, 5, 25, 26, C. I. Pigment Orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, 63, etc.

Carbon black as a black pigment, for example, MCF88, No.2300, 2200 B, 900, 33, 40, 45, 52, MA7, 8, 100, etc. (above trade names, Mitsubishi Chemical Corporation) Raven 5750, 5250, 5000, 3500, 1255, 700, etc. (above product names, Columbia Carbon Co.) Rega1 400 R, 330 R, 660 R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, etc. (above product names, Cabot) Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, V, 140 U, Special Black 6, 5, 4A, 4, etc. (above product names, Degussa), etc. there is

Since the ink composition according to the present invention is generally sprayed through a nozzle having a diameter of 10 to 50 μm, the average particle size of the pigment should be sufficiently small. In addition, the average particle size of the pigment greatly affects the stability and color development of the ink. The average particle size range of pigments that do not degrade the properties mentioned is usually about 0.005 to 15 μm. It should preferably have a particle size of 0.05 to 5 μm, more preferably an average particle size range of 100 to 200 nm is appropriate as an inkjet pigment.

The content of the pigment in the pigment dispersion composition according to the present invention is preferably 5 to 50% by mass, more preferably 10 to 30% by mass or less in the total dispersion composition (100% by mass), and one pigment alone or in combination with other pigments can be used together.

polymeric dispersant

The pigment dispersant used in the present invention refers to a polymer dispersant that imparts water dispersibility to organic pigments. The polymeric dispersant generally refers to one having a weight average molecular weight in the range of 50,000 to 200,000 as measured by gel permeation chromatography, and more generally having a molecular weight of 10,000 to 40,000.

As the polymer dispersant used in the pigment dispersion, a (meth)acrylate and (meth)acrylic acid copolymer or a styrene-acrylic acid copolymer is preferable, depending on the ratio of the monomers used during polymerization (i.e., hydrophobicity such as unsaturated acrylate). Monomer, hydrophilic monomer such as acrylic acid or hydroxy acryl) By adjusting the ratio of hydrophilic-hydrophobic properties, the adsorption force with the pigment and the dispersion force in an aqueous or oily medium can be controlled. In addition, it is possible to increase the fastness and gloss of the ink composition.

Monomers usable for copolymerization to prepare the dispersant include, for example, styrene, chlorostyrene, vinyltoluene, 2-ethylhexyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, butyl ( meth)acrylate, benzyl (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-phenoxy Ciethyl (meth)acrylate, tetrahydrofurryl (meth)acrylate, hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2 -Hydroxy-3-chloropropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, diethylamino (meth)acrylate, ethylhexyl acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate Latex, methoxytripropylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, p-nonylphenoxypolyethylene glycol (meth)acrylate, p-nonylphenone Polypropylene glycol (meth)acrylate, tetrafluoropropyl (meth)acrylate, 1,1,1,3,3,3-hexafluoroisopropyl (meth)acrylate, methyl α-hydroxymethyl acrylate ethyl α-hydroxymethyl acrylate, propyl α-hydroxymethyl acrylate, butyl α-hydroxymethyl acrylate, N-phenylmaleimide, N-(4-chlorophenyl)maleimide, methacrylic acid, maleic acid , or itaconic acid, etc., but is not limited thereto.

In addition, the dispersing agent is at least one dispersing agent selected from polyacrylate polymers, polystyrene-acrylate polymers, styrene maleic anhydride copolymers, and the like.

The polymeric dispersant may be characterized in that it has an acid value of 100 mgKOH/g or more and 300 mgKOH/g or less. If the acid value of the polymer dispersant is less than 100mgKOH/g, the water solubility is low, making it unsuitable for aqueous pigment dispersion application. On the other hand, if the acid value is more than 300mgKOH/g, the dispersant is not adsorbed on the surface of the pigment because of its high solubility in water. There is a problem that it is difficult to function as a dispersant because it exists in a dissolved state.

Volatile organic base compounds used to neutralize the polymeric dispersant include, for example, mono(methyl, ethyl, propyl) amines, di(methyl, ethyl, propyl) amines, tri(methyl, ethyl, propyl) amines of primary, secondary, and tertiary amines. (methyl, ethyl, propyl) amine, N,N-dimethylcyclohexyl amine, N,N-dimethylstearyl amine, N,N-dimethylaniline, N-methylpiperazine, N,N-dimethylethanol amine, N, N-diethylethanol amine, triethanolamine, N-methyldiethanolamine, dimethylaminopropanol, 2-methoxyethyldimethylamine, N-hydroxyethylpiperazine, 2-(2-dimethylaminoethoxy)-ethanol and 5-diethylamino-2-pentanone, 3-amino-1-propanol, N-ethylethanolamine, ammonia, and the like, but are not limited thereto. In addition, non-volatile base compounds include, for example, alkoxides, hydroxides, carbonates, or bicarbonate compounds of lithium, sodium, and potassium of monovalent alkali metals, but are not limited thereto.

Dispersing agents used in dispersing organic pigments may utilize commercially available dispersants, for example, Joncyl 693 or Joncryl 67 from BASF, Zetasperse 2500, Zetasperse 3100, Zetasperse 3400, Zetasperse 3600, or Zetasperse 3700 from Air Products, DISPERBYK from BYK. 194, DISPERBYK 2012, DISPER 2014, or BYKJET 9170, Lubrizol's Solsperse WV400, Huntsman's JEFFSPERSE X3204 or JEFFSPERSE X3503, but not limited thereto.

cross-linking agent

In the present invention, after dispersing the pigment with the dispersant, a crosslinking agent may be added to prepare an encapsulated pigment dispersion. Dispersants as described above generally contain salt forms of carboxylates, sulfonates and phosphonates and crosslinkable reactive groups such as hydroxyl groups.

Examples of the type of crosslinking agent used include compounds composed of groups such as epoxy, isocyanate, aziridine, carbodiimide, N-methylol, oxazoline, and silane.

A catalyst may be used because the encapsulated pigment dispersion prepared by the method described above reacts in the presence of a medium. In general, dibutyl-tin-dilaurate is mainly used for isocyanate reactions, and amine-based catalysts can be used for carboxylate or other types of acids.

A method of encapsulating a pigment with a dispersant can be prepared by mixing a pigment dispersion and a crosslinking agent and applying heat or a catalyst or adjusting the pH. After passing through the encapsulation process, the pH of the pigment dispersion may be corrected, filter treatment to remove coarse particles, or unreacted crosslinking agent may be removed and concentrated through a purification process to obtain an encapsulated pigment dispersion having desired physical properties.

other additives

Moisturizer, curing accelerator, adhesion promoter, filler, antifoaming agent, dissolution aid, penetration regulator, viscosity regulator, pH regulator, antioxidant, preservative, corrosion agent, etc. to maintain the deterioration prevention and storage stability of the encapsulated pigment dispersion composition provided in the present invention. Other additives may be used, such as inhibitors, chelating agents, preservatives or antiagglomerates.

Dispersion manufacturing process

As a method used for milling and dispersion treatment of the organic pigment dispersion, for example, a ball mill, a roll mill, a bead mill, a high-pressure homogenizer, or a high-speed stirrer may be used.

The organic pigment, neutralized polymer dispersing agent and water are added and stirred, and then dispersed using a bead mill. Bead mill beads are suitable for zirconium 0.1 ~ 0.5mm, filling rate 50 ~ 85%. The temperature at the time of dispersion is preferably 15 ° C or more and 40 ° C or less, or 20 ° C or more and 40 ° C or less. In order to suppress the generation of foam during dispersion, a defoaming agent or the like may be used together.

[Example]

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not to be construed as being limited by these examples. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Example 1: Preparation of encapsulated pigment dispersions

1-1: Preparation of Pigment Dispersion

Black pigment (carbon black, C. I. Pigment Black 7, product name S160, manufactured by Dagussa) 30 mass%, styrene-acrylic polymer dispersant neutralized with triethanolamine (Joncryl 693, Basf) 25% dispersant solution 30 mass% and water 40 Mixed with mass %. The mixture was dispersed with a dyno-mill at about 25 °C for 2 hours. The prepared dispersion was let-down to a solid content of 15% by mass based on the colorant, and then filtered to obtain a pigment dispersion (1) having a pH of 7.6 and an average particle size of 110 nm.

The same method as the preparation of the pigment dispersion was used, but as shown in Table 1 below, pigments (carbon black, C.I. Pigment Blue 15:3, C.I. Pigment Red 122, and C.I. Pigment Yellow 74), dispersant, content ratio, etc. In a different way, pigment dispersions (2) to (10) were prepared. In Table 1, the dispersant SA is a styrene-acrylic polymer dispersant (BASF Co.), and the SMA is a styrene maleic anhydride polymer dispersant (Air Products Co.).

Table 1

1-2: Preparation of encapsulated pigment dispersion

1.0 mass% of glycerol polyglycidyl ether (Denacol EX-313, epoxy content: 141, manufactured by Nagase ChemteX Co., Ltd.) was added as an epoxy crosslinking agent to 99.0 mass% of the pigment dispersion (1) (15 mass% of pigment) and stirred at room temperature, followed by stirring at 60 ° C. reacted for 4 hours. The reacted dispersion was filtered after cooling to room temperature to prepare an encapsulated pigment dispersion (1) having a pH of 7.7 and an average particle size of 115 nm.

Using the same method as the preparation of the encapsulated pigment dispersion, but, as shown in Table 2 below, the content of the pigment dispersion, the glycerol polyglycidyl ether used as a crosslinking agent, the reaction temperature and time, etc. were changed to obtain an encapsulated pigment dispersion ( 1-1) to (8) were prepared.

About 300 ml of each of the prepared encapsulated pigment dispersions were placed in 500 ml plastic bottles, hermetically sealed, and placed in a constant temperature water bath at 25° C. to stabilize the temperature of the dispersion, and average particle size, viscosity, pH, and filterability were measured at room temperature conditions.

The average particle size was measured three times (1 minute per measurement) using the dynamic light scattering method of Microtrac's NanotracTM 250 equipment, and the viscosity was measured by BROOKFEILD's LVDV-II B-type viscometer (CPE- 40 spindle standard). pH was measured using TOA's portable HM-20P pH METER, and filterability was measured using ADVANTEC's 0.8㎛ Syringe filter (CS080AN).

As can be seen in Table 2 below, all of the encapsulated pigment dispersions according to the present invention exhibited excellent physical properties, especially having a lower content of glycerol polyglycidyl ether than the encapsulated pigment dispersions (4) and (6). In the case of the encapsulated pigment dispersion, it was confirmed that the physical properties were very good with an average particle size of 130 nm or less and a filter property of 300 g or more.

Table 2

In addition, 3.0 mass% of an aziridine crosslinking agent (PZ-33, Polyaziridine LLC) was added to 97.0 mass% of the pigment dispersion (1) (15 mass% of pigment) and stirred at room temperature, followed by reaction at 65 ° C. for 8 hours.

The reacted dispersion was filtered after cooling to room temperature to prepare an encapsulated pigment dispersion (9) having a pH of 7.8, an average particle size of 118 nm, a viscosity of 4.3 cps, and a filterability of 500 g.

After adding and stirring 2.0 mass% of a crosslinking agent having a carbodiimide group (Carbodilite V-10, carbodiimide group content 410, Nisshinbo Chemical Inc.) to 98.0 mass% of the pigment dispersion (1) (15 mass% pigment) at room temperature, It was reacted at 75°C for 6 hours.

The reacted dispersion was filtered after cooling to room temperature to prepare an encapsulated pigment dispersion (10) having a pH of 7.6, an average particle size of 114 nm, a viscosity of 5.1 cps, and a filterability of 450 g.

It was confirmed that the encapsulated pigment dispersion prepared according to the present invention had low average particle size and viscosity, excellent filterability, and could be usefully used as a colorant for inkjet ink.

Example 2: Evaluation of encapsulated pigment dispersion properties

2-1: Evaluation of stability over time

Each of the six prepared encapsulated pigment dispersions was placed in about 15 ml, 20 ml glass vials, sealed, and stored at room temperature, 60° C., and 80° C. In order to measure the change in stability over time according to temperature, samples were collected by date, and the changes in average particle size, viscosity, pH, and filterability were measured under room temperature conditions, respectively, and are shown in Tables 3 and 4.

Table 3

Table 4

The encapsulated pigment dispersion prepared according to the present invention maintained the average particle size, viscosity, pH, and filterability when stored at room temperature, and maintained the average particle size, viscosity, and pH within a stable range over time when stored at high temperature, resulting in stability over time. It was confirmed to be very good.

2-2: Evaluation of solvent resistance of encapsulated pigment dispersion

Using the pigment dispersions (1), (3), (5), (9) and the encapsulated pigment dispersions (1), (3), (5), (8), (9) prepared in the present invention, Ink compositions (1) to (9) for digital textile printing were prepared with the compositions shown in Table 5. That is, each ink composition was prepared by mixing a pigment dispersion liquid or an encapsulated pigment dispersion liquid with a binder resin and a water-soluble organic solvent. In addition, the physical properties of the prepared ink compositions (1) to (9) are shown in Table 5 [UCOAT UWS-145 (polyester-based polyurethane, Sanyo Chemical); 1,2-hexanediol (Camtrose); Glycerin (LG Household & Health Care); BYK-348 (polyether modified siloxane, BYK); BT550 (1,2-benzisothiazolin-3-one, CDI)].

table 5

table 6

In the present invention, the ink compositions (1) to (4) prepared with the pigment dispersions (1), (3), (5), and (9) were inferior in physical properties and stability over time, but the pigment dispersions (1) and (3) Ink for digital textile printing prepared using encapsulated pigment dispersions (1), (3), (5), (8), (9) prepared by encapsulation reaction by adding a crosslinking agent to (5), (9) Compositions (5) to (9) have excellent average particle size and viscosity as shown in Table 6, and excellent stability over time at high temperature, so that physical properties suitable for inkjet printing pigment ink can be secured.

Having described specific parts of the present invention in detail above, it is clear that these specific descriptions are only preferred embodiments for those skilled in the art, and the scope of the present invention is not limited thereby. something to do. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (17)

Encapsulated pigment dispersion comprising:
(a) organic pigments;
(b) a polymeric dispersant;
(c) a cross-linking agent; and
(c) water. According to claim 1,
The organic pigment is an encapsulated pigment dispersion, characterized in that the average particle diameter of 50 ~ 200nm. According to claim 1,
The polymer dispersant is styrene, chlorostyrene, vinyltoluene, 2-ethylhexyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, Glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, tetrahydrofurril (meth)acrylate, hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-chloropropyl (meth)acryl rate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, diethylamino (meth)acrylate, ethylhexyl acrylate, 2-methoxyethyl (meth)acrylate, 3 -Methoxybutyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxytripropylene glycol (meth)acrylate , methoxy polyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, p-nonylphenoxypolyethylene glycol (meth)acrylate, p-nonylphenoxypolypropylene glycol (meth)acrylate, tetrafluoro Ropropyl (meth)acrylate, 1,1,1,3,3,3-hexafluoroisopropyl (meth)acrylate, methyl α-hydroxymethyl acrylate, ethyl α-hydroxymethyl acrylate, propyl At least one selected from the group consisting of α-hydroxymethyl acrylate, butyl α-hydroxymethyl acrylate, N-phenylmaleimide, N-(4-chlorophenyl)maleimide, methacrylic acid, maleic acid, and itaconic acid An encapsulated pigment dispersion, characterized in that it is prepared by polymerization. According to claim 1,
The polymeric dispersant is an encapsulated pigment dispersion, characterized in that it comprises at least one selected from the group consisting of polyacrylate polymer, polystyrene-acrylate polymer, and styrene maleic anhydride copolymer. According to claim 1,
The encapsulated pigment dispersion, characterized in that the polymer dispersant has an acid value of 100 mgKOH / g or more and 300 mgKOH / g or less. According to claim 1,
The encapsulated pigment dispersion, characterized in that the crosslinking agent comprises at least one reactive group selected from the group consisting of epoxy, isocyanate, aziridine, carbodiimide, n-methylol, oxazoline and silane. According to claim 1,
The encapsulated pigment dispersion comprises 10 to 50% by mass of an organic pigment, 5 to 25% by mass of a polymer dispersant, 1 to 10% by mass of a crosslinking agent, and 15 to 84% by mass of water, based on 100% by mass of the encapsulated pigment dispersion. dispersion. According to claim 1,
The encapsulated pigment dispersion is characterized in that the encapsulated pigment dispersion is used for ink for inkjet, paint, coating, fiber, or colorant for stationery. According to claim 1,
The encapsulated pigment dispersion, characterized in that the encapsulated pigment dispersion has a viscosity of 3 to 15 cps. According to claim 1,
The encapsulated pigment dispersion has a filterability of 20 to 500 g based on a 0.8 μm syringe filter. A method for preparing an encapsulated pigment dispersion comprising the following steps:
(a) adding and mixing an organic pigment, a polymer dispersant and water;
(b) with a bead mill, preparing an organic pigment dispersion; and
(c) reacting by adding a crosslinking agent. According to claim 11,
The organic pigment is a method for producing an encapsulated pigment dispersion, characterized in that the average particle diameter of 50 ~ 200nm. According to claim 11,
The polymer dispersant is styrene, chlorostyrene, vinyltoluene, 2-ethylhexyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, Glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, tetrahydrofurril (meth)acrylate, hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-chloropropyl (meth)acryl rate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, diethylamino (meth)acrylate, ethylhexyl acrylate, 2-methoxyethyl (meth)acrylate, 3 -Methoxybutyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxytripropylene glycol (meth)acrylate , methoxy polyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, p-nonylphenoxypolyethylene glycol (meth)acrylate, p-nonylphenoxypolypropylene glycol (meth)acrylate, tetrafluoro Ropropyl (meth)acrylate, 1,1,1,3,3,3-hexafluoroisopropyl (meth)acrylate, methyl α-hydroxymethyl acrylate, ethyl α-hydroxymethyl acrylate, propyl At least one selected from the group consisting of α-hydroxymethyl acrylate, butyl α-hydroxymethyl acrylate, N-phenylmaleimide, N-(4-chlorophenyl)maleimide, methacrylic acid, maleic acid, and itaconic acid Method for producing an encapsulated pigment dispersion, characterized in that produced by polymerization. According to claim 11,
The method for producing an encapsulated pigment dispersion, characterized in that the polymeric dispersant comprises at least one selected from the group consisting of polyacrylate polymer, polystyrene-acrylate polymer, and styrene maleic anhydride copolymer. According to claim 11,
The method for producing an encapsulated pigment dispersion, characterized in that the crosslinking agent comprises at least one reactive group selected from the group consisting of epoxy, isocyanate, aziridine, carbodiimide, n-methylol, oxazoline and silane. According to claim 11,
In the step (b), the organic pigment dispersion is prepared by dispersing at a temperature of 15 to 40 ° C using a bead mill. According to claim 11,
In the step (c), a crosslinking agent is added and reacted at a temperature of 30 to 80 ° C. to prepare an encapsulated pigment dispersion.