JP4396210B2 - Pigment dispersant, pigment composition, and pigment dispersion - Google Patents

Description

  The present invention relates to a pigment dispersant used for dispersing pigment particles, and more particularly to a pigment dispersant effective for inks and paints, a pigment composition containing the same, and a pigment dispersion. .

  Generally, in various coatings or ink compositions, a practically useful pigment that exhibits a clear color tone and high coloring power is composed of fine particles. However, when fine particles of pigment are dispersed in non-aqueous vehicles such as offset inks, gravure inks and paints, it is difficult to obtain a stable dispersion, which has a significant impact on manufacturing operations and the value of the resulting product. It is known to cause various problems.

  For example, dispersions containing pigments consisting of fine particles often exhibit high viscosity, making it difficult not only to remove the product from the disperser and to transfer it from the disperser to a tank, etc. It may become difficult to use due to gelation. In addition, when different types of pigments are mixed and used, phenomena such as color separation or sedimentation due to aggregation of pigments may cause uneven color and a marked decrease in coloring power in the developed product. In addition, the surface of the coating film of the color-extended product may cause a state failure such as a decrease in gloss and a leveling failure. Although not directly related to the dispersion of the pigment, some organic pigments have a phenomenon accompanied by a change in the crystal state of the pigment. That is, in the case of offset inks, gravure inks, paints, etc., pigment crystal particles that were in an unstable state in a non-aqueous vehicle change their size, form, etc., and shift to a stable state. For this reason, the product value may be impaired by a remarkable hue change, coloring power reduction, generation of coarse particles, and the like in the color-extended product.

  In order to solve the various problems as described above, in various fields in which pigments are dispersed, pigment derivatives in which a functional group such as an acidic group, a basic group, or a phthalimidomethyl group is introduced into the pigment skeleton, or Resin-type pigment dispersants in which an acidic group or basic group is introduced into a part of an acrylic polymer or polyester resin have been developed and used alone or in combination, and are extremely effective. In addition, so-called resin-type pigment derivatives in which a pigment skeleton is bonded to a part of the resin have been developed.

Among these, pigment derivatives having an acidic group (hereinafter referred to as acidic pigment derivatives) are pigment skeletons such as phthalocyanine pigments, quinacridone pigments, azo pigments, anthraquinone pigments, diketopyrrolopyrrole pigments, and isoindoline pigments. On the other hand, the structure which introduce | transduced the acidic group of the sulfonic acid group or the carboxyl group is disclosed, and it has been used for a long time as a dispersing agent or particle growth inhibitor. In recent years, this technology has been widely deployed in color filter inks. However, although high transparency can be obtained by these, the viscosity, flow characteristics and viscosity stability with time have not been sufficiently satisfied (see Patent Document 1 and Patent Document 2).
JP 09-176511 A JP 2002-179799 A

  The problem to be solved is to provide inks and paints that improve the flow characteristics in inks and paints, have low viscosity and low thixotropic properties, and have good viscosity stability over time.

（式中、Ｘは塩素、臭素、沃素のハロゲン原子を表し、ｎ，ｍはそれぞれ独立して０〜４の整数であり、置換ハロゲン原子数を表す。） The main feature of the present invention is that a quinoline derivative represented by the following general formula (1) or (2) or a compound comprising an amine salt or a metal salt thereof is used as a pigment dispersant.

(In the formula, X represents a halogen atom of chlorine, bromine or iodine, and n and m are each independently an integer of 0 to 4 and represent the number of substituted halogen atoms.)

Using the pigment dispersant, pigment composition, and pigment dispersion of the present invention, not only has excellent non-aggregability, non-crystallinity, gloss and transparency of the coating film, but also low viscosity, low thixotropic properties, viscosity over time. Ink and paint having good stability can be obtained.

  In the pigment dispersant of the present invention, the amine used for the amine salt is ammonia, dimethylamine, trimethylamine, diethylamine, triethylamine, hydroxyethylamine, dihydroxyethylamine, 2-ethylhexylamine, N, N-dimethylaminopropylamine, N, Long-chain alkylamines having an alkyl group having 12 or more carbon atoms such as lower amines such as N-diethylaminopropylamine and N, N-dibutylaminopropylamine, laurylamine, oleylamine, palmitylamine, stearylamine, dimethyllaurylamine, Long chain alkyls having 12 or more carbon atoms such as lauryltrimethylammonium, dilauryldimethylammonium, stearyltrimethylammonium, distearyldimethylammonium Kill quaternary ammonium ion. Among these, when a long-chain alkylamine having an alkyl group having 12 or more carbon atoms such as laurylammonium and stearylammonium is used, the effect is the highest.

  In the pigment dispersant of the present invention, examples of the metal used in the metal salt include various metals such as sodium, potassium, calcium, barium, iron, magnesium, aluminum, nickel, cobalt, and strontium. Among these, the aluminum salt exhibits not only excellent isolation in production and dispersibility as a pigment dispersant, but also exhibits the most excellent effects in low viscosity, flow characteristics, and stability over time.

  The quinoline derivatives of general formula (1) and general formula (2) of the present invention are synthesized through the following three steps. That is, first, C.I. I. A step of sulfonating phthalimidoquinophthalone represented by Pigment Yellow 138 with sulfuric acid or fuming sulfuric acid. Second, the obtained sulfonated product is redispersed in water and then hydrolyzed under an alkali having a pH of 11 or more. Thirdly, the alkali hydrolyzate is reacted with an amine or a metal to form a salt. Hereinafter, each process will be described in detail.

  The sulfonation as the first step can be performed according to a known method. For example, C.I. I. Pigment Yellow 138 is dissolved in sulfuric acid, fuming sulfuric acid, a mixture of sulfuric acid and fuming sulfuric acid, chlorosulfonic acid and the like, and a heating reaction is performed at 40 to 140 ° C. for 1 to 8 hours as a reaction time. The progress of sulfonation can be confirmed by component analysis by liquid chromatography or change in absorption spectrum of sulfuric acid solution, and the end point of the reaction can be traced and determined. After confirming sufficient sulfonation, the sulfuric acid reaction solution was dropped into a large amount of ice water, the precipitated sulfonated product was filtered off, washed with dilute hydrochloric acid, and further washed with purified water. I. Pigment Yellow 138 sulfonated product is isolated as a paste.

  The alkali hydrolysis of the sulfonated product as the second step follows the following method. After the sulfonated paste obtained in the first step is redispersed in about 100 times water, the pH is adjusted to 11 or more with a caustic soda solution and stirred for 1 to 10 hours. By adjusting the pH to 11 or more, the reaction solution changes from a yellow slurry state in which undissolved particles are dispersed to a dissolved red solution state. The progress of the alkaline hydrolysis reaction can be confirmed by liquid chromatography. In some cases, the hydrolysis reaction is sufficiently advanced by heating and stirring at a temperature of 50 ° C. or higher for 4 to 24 hours while maintaining pH 11 or higher.

  The salt formation reaction with an amine or metal, which is the third step, follows the following method. For the red aqueous solution of the alkaline hydrolyzate obtained in the second step, various amine aqueous solutions or water-soluble organic solvent solutions such as alcohols, or powders of metal hydrochlorides, sulfates, nitrates, etc. Alternatively, the aqueous solution is slowly added over 10 minutes to 5 hours to carry out the salt formation reaction. The amount of amine or metal to be added is added until bleeding stops, but an equimolar to 5-fold molar amount is generally used. Thereafter, the precipitated product is filtered off, sufficiently washed with water and dried to obtain the desired product.

  As the pigment used in the pigment composition, pigment dispersion, and ink composition of the present invention, various commercially available pigments can be used. For example, azo, anthanthrone, anthrapyrimidine, anthraquinone, isoindolinone, isoindoline, indanthrone, quinacridone, quinophthalone, dioxazine, diketopyrrolopyrrole, thioindigo dye, Organic pigments such as pyranthrone dyes, phthalocyanine dyes, flavanthrone dyes, perinone dyes, perylene dyes, benzimidazolone dyes, carbon black, titanium oxide, yellow lead, cadmium yellow, cadmium red, petal, iron black It can be used for inorganic pigments such as zinc white, bitumen and ultramarine. These pigments may be used in combination.

Among these various pigments, non-aggregation, non-crystallinity, fluidity, and the like are significant for pigments having the same or similar chemical structure as the pigment dispersant of the present invention. They are pigments partially having a benzene ring in which four adjacent atoms are substituted with halogens as chemical structures; I. Pigment Yellow 138 quinophthalone pigment, C.I. I. Pigment Green 7, C.I. I. Halogenated phthalocyanine pigments such as C.I. Pigment Green 36; I. Pigment Yellow 109, C.I. I. Pigment Yellow 110 and other isoindolinone pigments.

  In the pigment composition of the present invention, the pigment dispersant represented by the general formula (1) and the general formula (2) is added to the pigment alone or in combination with the resin-type pigment dispersant. It is. Resin-type pigment dispersants used in the pigment composition of the present invention are disclosed in JP-A-60-166318, JP-A-61-174939, JP-A-46-7294, and JP-A-09-169821. And the like, and those having a weight average molecular weight of 1,000 to 100,000. If the weight average molecular weight of the resin-type pigment dispersant is less than 1000, sufficient steric hindrance cannot be obtained, and the dispersion effect is lowered. The amine value of the resin type pigment dispersant is preferably 5 to 200 mg KOH / g. If it is less than 5 mg KOH / g, the interaction with the pigment dispersant of the present invention tends to be insufficient, and even if the pigment dispersant of the present invention is adsorbed on the pigment surface, a sufficient dispersion effect may not be obtained. On the other hand, if the amine value of the resin-type pigment dispersant exceeds 200 mgKOH / g, the steric hindrance layer is reduced as compared with the affinity part for the pigment component, and the dispersion effect tends to be insufficient. Examples of such resin-type pigment dispersants include Solsperse 24000 (manufactured by Geneca Corporation), Disperbyk-160, Disperbyk-161, Disperbyk-162, Disperbyk-163, Disperbyk-170 (manufactured by BYK Chemie), etc. Ajisper PB821 (manufactured by Ajinomoto Co., Inc.).

  In the pigment composition of the present invention, the addition amount of the pigment dispersant represented by the general formula (1) and the general formula (2) is preferably 0.5 to 30 parts by weight with respect to 100 parts by weight of the pigment. The addition amount of the pigment dispersant is preferably 0.5 to 100 parts by weight with respect to 100 parts by weight of the pigment. When the addition amount of the pigment dispersant represented by the general formula (1) and the resin type pigment dispersant is less than 0.5 parts by weight, the pigment dispersion effect is small, which is not preferable. Moreover, even if the addition amount of the pigment dispersant represented by the general formula (1) is used more than 30 parts by weight, the effect of the used amount cannot be obtained, and the addition amount of the resin type pigment dispersant is used more than 100 parts by weight. In addition, the effect may not be obtained, and the physical properties of the coating film may be lowered.

  As a method for preparing the pigment composition of the present invention, a sufficient dispersion effect can be obtained by simply mixing the pigment powder and the powder of the pigment dispersant of the present invention. However, a dissolver, a high speed mixer, a homomixer, a kneader, a roll mill Then, mechanically mix using an attritor, sand mill, various pulverizers, etc., or add a solution containing the pigment dispersant of the present invention to the suspension system of pigment water or organic solvent, and apply the pigment dispersant to the pigment surface. Even better results can be obtained by using a wise mixing method such as depositing or co-dissolving the organic pigment and the pigment dispersant in a solvent with strong dissolving power such as sulfuric acid and co-precipitation with a poor solvent such as water. Obtainable.

Examples of the method of using the pigment dispersant according to the present invention include the following methods.
1. A pigment composition obtained by previously mixing a pigment and a pigment dispersant is added to a non-aqueous vehicle and dispersed.
2. A pigment and a pigment dispersant are separately added and dispersed in a non-aqueous vehicle.
3. A dispersion obtained by separately dispersing a pigment and a pigment dispersant in advance in a non-aqueous vehicle is mixed. In this case, the pigment dispersant may be dispersed only with a solvent.
4). After the pigment is dispersed in the non-aqueous vehicle, a pigment dispersant is added to the obtained pigment dispersion.
Any of these methods can achieve the intended effect.

  The pigment composition of the present invention is mixed with various organic solvents, resins (varnishes), additives, commercial dispersants, etc. as necessary, and dispersed by a horizontal sand mill, vertical sand mill, annular bead mill, attritor or the like. A pigment dispersion in which the pigment composition is dispersed in a non-aqueous vehicle can be produced. The pigment, pigment dispersant, resin (varnish), resin-type dispersant, additive, and organic solvent may be dispersed after mixing all the components, but first the pigment and the pigment dispersant of the present invention are organically mixed. It is desirable to disperse in a solvent and then add and disperse a resin-type dispersant and resin.

  Also, before dispersing with a horizontal sand mill, vertical sand mill, annular bead mill, attritor, etc., pre-dispersion using a kneader mixer such as a kneader, 3-roll mill, solid dispersion with 2-roll mill, etc., or pigment The pigment derivative may be treated. In addition, after being dispersed in a bead mill or the like, post-treatment is said to be stored for several hours to one week in a heated state at 30 to 80 ° C., or post-treatment using an ultrasonic disperser or a collision-type beadless disperser. This step is effective for the stability of the dispersion. In addition, any disperser or mixer such as a microfluidizer, a high speed mixer, a homomixer, a ball mill, a roll mill, a stone mill, or an ultrasonic disperser can be used for producing the dispersion of the present invention.

  Examples of the non-aqueous vehicle used in the pigment dispersion of the present invention include petroleum resin, casein, shellac, rosin-modified maleic resin, rosin-modified phenol resin, nitrocellulose, cellulose acetate butyrate, cyclized rubber, chlorinated rubber, Oxidized rubber, hydrochloric acid rubber, phenolic resin, alkyd resin, polyester resin, unsaturated polyester resin, amino resin, epoxy resin, vinyl resin, vinyl chloride, vinyl chloride-vinyl acetate copolymer, acrylic resin, methacrylic resin, polyurethane resin, Examples include silicone resins, fluororesins, drying oils, synthetic drying oils, styrene-modified maleic acid, polyamide resins, polyimide resins, benzoguanamine resins, melamine resins, urea resins, chlorinated polypropylene, butyral resins, and vinylidene chloride resins.

  A photosensitive resin can also be used as the non-aqueous vehicle. Examples of the photosensitive resin include (meth) acrylic compounds having a reactive substituent such as an isocyanate group, an aldehyde group, and an epoxy group on a linear polymer having a reactive substituent such as a hydroxyl group, a carboxyl group, or an amino group, A resin obtained by reacting an acid and introducing a photocrosslinkable group such as a (meth) acryloyl group or a styryl group into the linear polymer is used. Further, a linear polymer containing an acid anhydride such as a styrene-maleic anhydride copolymer or an α-olefin-maleic anhydride copolymer is converted into a (meth) acrylic compound having a hydroxyl group such as hydroxyalkyl (meth) acrylate. Half-esterified products are also used.

  As the solvent, any solvent generally used as an organic solvent can be used. For example, cyclohexanone, ethyl cellosolve acetate, butyl cellosolve acetate, propylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether, ethylbenzene, ethylene glycol diethyl ether, toluene, xylene, ethyl cellosolve, methyl-n amyl ketone, propylene glycol monomethyl ether, toluene, methyl ethyl ketone, methyl isobutyl ketone , Ethyl acetate, butyl acetate, n-hexane, methanol, ethanol, isopropyl alcohol, butanol, dioxane, dimethylformamide, Solvesso 100 (manufactured by Exxon Chemical Co., Ltd.), Swazol 1000, petroleum solvent, etc. Used by mixing.

  Hereinafter, the present invention will be described by way of examples. In the examples, “part” represents “part by weight” and “%” represents “% by weight”.

Production Example 1
<Synthesis of quinoline derivative [A]>
In a 500 ml four-necked flask, 450 parts of 101% sulfuric acid prepared from fuming sulfuric acid (25% SO ₃ ) and sulfuric acid were charged. I. 45 parts of Pigment Yellow 138 (Parisol Yellow K0961-HD, manufactured by BSF) was added little by little. Stirring was performed at 80 ° C. for 3 hours, and disappearance of raw materials was confirmed by liquid chromatography. The reaction solution was added to 5000 parts of ice water with stirring to precipitate a sulfonated product. Next, the mixture was filtered, washed with 2000 parts of 0.1% hydrochloric acid, and further washed with 2000 parts of purified water. I. A sulfonated paste of Pigment Yellow 138 was obtained. The obtained sulfonated paste was redispersed in 5000 parts of water (pH of the redispersed slurry was 2.3), and 25% caustic soda solution was added with stirring to adjust the pH to 11.5. During the pH adjustment, the reaction solution changed from a yellow slurry state to a red solution state. The pH was finely adjusted every 5 minutes and continued for 1 hour. Furthermore, it heated at 60 degreeC at pH11.5, and stirred for 3 hours. To this red solution, an aqueous solution in which 47 parts of aluminum chloride (hexahydrate) was dissolved was added dropwise little by little to obtain a yellow precipitate. The pH after addition of the entire amount was 3.5. The yellow precipitate was filtered off, washed with a large amount of water, and then dried at 80 ° C. to obtain 40 parts of a quinoline derivative [A].

<Analysis of Quinoline Derivative [A]>
The obtained quinoline derivative [A] was dissolved in DMF and analyzed using an LC / MS analyzer “Platform LCZ” (ESI: Electron Spray System) manufactured by Nippon Waters. As a result, m / z = 809 [M−1] ⁻ was detected at the largest peak at an area ratio of 70% at 420 nm. This coincides with the molecular ion of the quinoline derivative in which n = 4, m = 4, and X is a chlorine atom in the general formula (2). Further, in order to measure the amount of aluminum contained in the quinoline derivative, the intensity ratio of aluminum atoms and chlorine atoms contained in the quinoline derivative [A] was determined using a fluorescent X-ray apparatus “SXF1200” manufactured by Shimadzu Corporation. At this time, a calibration curve for determining the amount of aluminum contained in the quinoline derivative is C.I. I. Pigment Yellow 138 sulfonated product was mixed with aluminum oxide powder at an arbitrary ratio, and the strength ratio of each aluminum atom and chlorine atom was measured. As a result, it is clear that the number of aluminum is 3.06 per molecule of the quinoline derivative [A], and one sulfonic acid and two carboxylic acids each coordinate with aluminum. I found out.

Production Example 2
<Synthesis of quinoline derivative [B]>
In a 500 ml four-necked flask, 450 parts of fuming sulfuric acid (25% SO ₃ ) were charged. I. 45 parts of Pigment Yellow 138 (Parisol Yellow K0961-HD, manufactured by BSF) was added little by little. Stirring was performed at 70 ° C. for 1 hour, and disappearance of the raw materials was confirmed by liquid chromatography. The reaction solution was added to 5000 parts of ice water with stirring to precipitate a sulfonated product, filtered off, washed with 2000 parts of 0.1% hydrochloric acid, and further washed with 2000 parts of water. I. A sulfonated paste of Pigment Yellow 138 was obtained. The obtained sulfonated paste was redispersed in 5000 parts of water (the pH of the redispersed slurry was 2.3), and 25% sodium hydroxide solution was added with stirring to adjust the pH to 11.5. The pH was finely adjusted every 5 minutes and continued for 1 hour. The reaction solution was red dissolved. To this red solution, an aqueous solution in which 30 parts of calcium chloride (dihydrate) was dissolved was dropped little by little to obtain a yellow precipitate. After filtration, washing with a large amount of water and drying at 80 ° C., 40 parts of quinoline derivative [B] was obtained.

<Analysis of Quinoline Derivative [B]>
The obtained quinophthalone derivative [B] was dissolved in DMF and analyzed using an LC / MS analyzer “Platform LCZ” (ESI: Electron Spray Method) manufactured by Nippon Waters. As a result, m / z = 791, 809 [M−1] ⁻ was detected in two large peaks of the chromatograph at 420 nm. This is consistent with the molecular ion of the quinoline derivative in which n = 4, m = 4, and X is a chlorine atom in the general formulas (1) and (2). Further, in order to measure the amount of aluminum contained in the quinoline derivative, the intensity ratio of calcium atoms and chlorine atoms contained in the quinoline derivative [B] was determined using fluorescent X-rays. At this time, a calibration curve for determining the amount of calcium contained in the quinoline derivative is C.I. obtained as an intermediate. I. Pigment Yellow 138 sulfonated product was prepared by mixing calcium oxide at an arbitrary ratio and measuring the strength ratio of each calcium atom and chlorine atom. As a result, it is clear that the number of calcium is 2.56 with respect to one molecule of the quinoline derivative [B], and one sulfonic acid in general formulas (1) and (2) and 1 to It was found that each of the two carboxylic acids is coordinated with calcium.

Production Example 3 <Synthesis of Quinoline Derivative [C]>
In accordance with the synthesis of the quinoline derivative [B] in Production Example 2, an aqueous solution in which 36 parts of coconut oil amine acetate (trade name: Acetamine 24, manufactured by Kao Corporation) was dissolved in hot water instead of calcium chloride was used. Were carried out in the same manner to obtain 43 parts of a quinoline derivative [C].

Comparative Production Example 1 <Synthesis and Analysis of Compound [D]>
C. I. 6 parts of Pigment Yellow 138 (Paritor Yellow D0960 manufactured by BSF Corporation) was added to 78 parts of fuming sulfuric acid (25% SO ₃ ) at 15 ° C. with stirring. After stirring for 3 hours, it was added onto 150 parts of ice. After standing for 30 minutes, the resulting suspension was filtered and the resulting product was washed with 30 parts of water. The product was put into 200 parts of water and neutralized with an aqueous ammonia solution (added aqueous ammonia until pH was 7). 45 parts of ammonium chloride was added and stirred at 80 ° C. for 30 minutes, and the deposited precipitate was filtered at 60 ° C. The obtained wet crystals were washed with water and then dried at 80 ° C. to obtain 10 parts of Pigment Yellow 138 sulfonated product (hereinafter referred to as Compound [D]). The obtained compound [D] was dissolved in DMF and analyzed using an LC / MS analyzer “Platform LCZ” (ESI: electron spray method) manufactured by Japan Waters. As a result, in the largest peak of the chromatograph at 420 nm, m / z = 773 [M−1] ⁻ was detected. Further, the retention time in the chromatograph was clearly different from the retention times of the peaks at m / z = 791, 809 [M−1] ⁻ in Production Example 1 or 2.

Comparative Production Example 2 <Synthesis and Analysis of Compound [E]>
In a 500 ml four-necked flask, 300 parts of 98% sulfuric acid was placed. I. 20 parts of Pigment Yellow 138 (Parisol Yellow K0961-HD, manufactured by BSF) was added little by little. The reaction was carried out at 120 ° C. for 5 hours to obtain a sulfonated product of a phthalimidoquinophthalone compound. The reaction mixture was poured into 3000 parts of water with stirring to precipitate a sulfonated product of a phthalimidoquinophthalone compound, stirred for 30 minutes, and then filtered and washed with water three times. The obtained wet cake was washed with 300 parts of 1% dilute sulfuric acid, filtered, washed with water, equimolar potassium hydroxide was added, the pH was adjusted to 9, and the potassium salt of quinophthalone sulfonic acid was adjusted. Next, equimolar calcium chloride was added to precipitate the calcium salt of quinophthalone sulfonic acid, filtered, and washed with water until the pH of the wash water reached 7-6. After drying in a hot air dryer, 57 parts of a quinophthalone derivative (calcium quinophthalone sulfonate, hereinafter referred to as compound [E]) was obtained. The obtained compound [E] was dissolved in DMF and analyzed using LC / MS analyzer “Platform LCZ” (ESI: electron spray method) manufactured by Japan Waters Co. As a result, in the largest peak of the chromatograph at 420 nm, m / z = 773 [M−1] ⁻ was detected. Further, it was clearly different from the retention time of the peak of m / z = 791, 809 [M−1] ⁻ in Production Example 1 or 2.

Comparative Production Example 3 <Synthesis and Analysis of Compound [F]>
A 5 L beaker was charged with 400 parts of ice and 1400 parts of water, and 200 g of potassium hydroxide was added little by little with stirring to dissolve. Among these, C.I. I. 200 parts of Pigment Yellow 138 (Pariotor Yellow K0961-HD manufactured by BSF) was charged and reacted at 90 ° C. for 8 hours. After cooling to room temperature, 270 ml of 36% hydrochloric acid was added dropwise. After filtration, washing with water and vacuum drying, compound “F” was obtained. The obtained compound [F] was dissolved in DMF and analyzed using a LC / MS analyzer “Platform LCZ” (ESI: electron spray method) manufactured by Japan Waters Co. As a result, in the largest peak of the chromatograph at 420 nm, m / z = 729 [M−1] ⁻ was detected. This is consistent with the molecular ion of the quinoline derivative that has no sulfonic acid group in the general formula (2) (the sulfonic acid group is substituted with a hydrogen atom), n = 4, m = 4, and X is a chlorine atom. To do.

(Preparation of acrylic resin solution 1)
A separable four-necked flask was equipped with a thermometer, a condenser tube, a nitrogen gas inlet tube, and a stirrer and charged with 70.0 parts of cyclohexanone. 13.3 parts of methacrylate, 4.6 parts of 2-hydroxyethyl methacrylate, 4.3 parts of methacrylic acid, 7.4 parts of paracumylphenol ethylene oxide modified acrylate (Aronix M110 manufactured by Toagosei Co., Ltd.), 2,2′-azobis A mixed solution of 0.4 part of isobutyronitrile was added dropwise over 2 hours. After completion of the dropwise addition, the reaction was continued for 3 hours to obtain an acrylic resin solution having a solid content of 30% and a weight average molecular weight of 26000.
After cooling to room temperature, about 2 g of the resin solution was sampled, heated and dried at 180 ° C. for 20 minutes to measure the nonvolatile content, and cyclohexanone was added to the previously synthesized resin solution so that the nonvolatile content was 20% by weight. Thus, an acrylic resin solution 1 was prepared.

(Preparation of acrylic resin solution 2)
A reaction vessel was charged with 800 parts of cyclohexanone, heated to 100 ° C. while injecting nitrogen gas into the vessel, and a mixture of the following monomer and thermal polymerization initiator was added dropwise at the same temperature over 1 hour to carry out a polymerization reaction.
60.0 parts of styrene
Methacrylic acid 60.0 parts
Methyl methacrylate 65.0 parts
Butyl methacrylate 65.0 parts
Azobisisobutyronitrile 10.0 parts After the addition, the mixture was further reacted at 100 ° C. for 3 hours, and then 2.0 parts of azobisisobutyronitrile dissolved in 50 parts of cyclohexanone was added. The reaction was continued for 1 hour to obtain an acrylic resin solution having a weight average molecular weight of about 40,000.
After cooling to room temperature, about 2 g of the resin solution was sampled, heated and dried at 180 ° C. for 20 minutes to measure the nonvolatile content, and cyclohexanone was added to the previously synthesized resin solution so that the nonvolatile content was 20% by weight. Thus, an acrylic resin solution 2 was prepared.

[Example 1]

As shown in Table 1, the quinoline derivatives [A] to [C] obtained in Production Examples 1 to 3 as various pigments and pigment dispersants, or the compounds [D] to [C] obtained in Comparative Production Examples 1 to 3 were used. F], acrylic resin solution 1 or resin solution 2 shown above as a non-aqueous vehicle, Ajinomoto Co., Ltd. “Ajisper PB821”, or Zeneca Co., Ltd. “Solspers SP-24000” Cyclohexanone was blended as a solvent, and dispersion was performed for 6 hours together with 200 g of zirconia beads having a diameter of 1.25 mm using a paint conditioner to prepare a pigment dispersion.

(Evaluation of each dispersion)
The viscosity and thixo index value (TI value) of each dispersion were measured using a B-type viscometer. Further, the gloss of a coating film applied to a PET film with a wet thickness of 12 μm and dried at 150 ° C. for 2 minutes was measured. Further, the viscosity increase rate after storage at 40 ° C. for 2 weeks was measured, and the results were ◎ (there was almost no thickening), ○ (slightly thickening was observed but usable range), Δ (thickening was observed) Cannot be used), x (noticeable due to significant thickening). These results are summarized in Table 1. As shown in Table 1, those using the pigment dispersant of the present invention have low viscosity, small thixotropic properties, and excellent fluidity close to Newtonian (TI value close to 1). Moreover, the viscosity stability over time was also good.

By using the pigment dispersant, the pigment composition, and the pigment dispersion of the present invention, not only the non-assembly property, the non-crystallinity, the gloss of the coating film and the transparency are excellent, but also the low viscosity, the low thixotropic property, Easy to obtain inks and paints with good viscosity stability, gravure inks, various general paints for automobiles, woods, metals, etc., back coat paints for magnetic tapes, radiation cure inks, and inkjet printers It can be used for applications such as inks and color filter inks.

Claims (4)

A pigment dispersant comprising a quinoline derivative represented by the following general formula (1) or (2) or an amine salt or a metal salt thereof.

(In the formula, X represents a halogen atom of chlorine, bromine or iodine, and n and m are each independently an integer of 0 to 4 and represent the number of substituted halogen atoms.)   A pigment composition comprising the pigment and the pigment dispersant according to claim 1.   A pigment composition comprising a pigment, the pigment dispersant according to claim 1, and a resin-type pigment dispersant having a weight average molecular weight of 1,000 to 100,000. A pigment dispersion obtained by dispersing the pigment composition according to claim 2 or 3 in a non-aqueous vehicle.