JPH09157538A - Pigment dispersant and coating mateiral or printing ink composition containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pigment dispersant improved in the ability to disperse a pigment, the flowability of a mill base, the capability of giving a pigment dispersion having good storage stability, etc., by using a reaction product between a hydroxyl-terminated polyester components and a carboxylic polymer component. SOLUTION: This pigment dispersant comprises a reaction product between a hydroxyl-terminated polyester component having a number-average molecular weight of 100-10,000 and obtained by reacting a monohydric alcohol represented by formula I [wherein R<1> is a 1-24C hydrocarbon group or RO(CH2 ZCH2 O)n CH2 CH2 OH; R is an aliphatic alkyl; and (n) is 1-3] with a lactone compound represented by formula II (wherein R<1> is a 1-10C aliphatic alkylene) or a 2-40C hydroxycarboxylic acid and a carboxylic polymer component comprising structural units represented by formula III (wherein R<4> to R<10> are each H or a 1-10C alkyl; and n1 , n2 and n3 are each 0-10) or structural units represented by formula IV (wherein R<11> is R<4> ) and having a number-average molecular weight of 100-100,000, an alkali metal salt thereof or an ammonium salt thereof.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pigment dispersant and a composition containing the same. More specifically, the present invention relates to a dispersant used for improving the dispersibility of a pigment when preparing a coating material, an ink, and the like, and a composition containing the dispersant.

[0002]

2. Description of the Related Art Conventionally, when preparing paints, inks, etc., the dispersibility of the pigments contained therein is improved, the storage stability of the paints, the prevention of color separation phenomenon, the gloss of the coating film, etc. are improved. For the purpose of, various dispersants are used.
For example, a dispersant having a structure in which a polyamine compound and a polyester or an acrylic resin are bonded is disclosed in JP-A-61-174939 or JP-A-63-19.
No. 7529, JP-A-54-37082, JP-A-48-79178 and the like have been proposed.

[0003]

Among these conventionally proposed dispersants, a dispersant having a polyamine structure in its molecular chain has a function of being adsorbed by a pigment,
It is effective for a specific pigment having an acidic adsorption point on the pigment surface, but does not necessarily show good dispersibility for a pigment having a low acidity on the surface and having no effective adsorption point. Furthermore, in the case of a paint prepared by using a dispersant having a polyamine structure, there are cases in which problems such as coloring during baking of the coating film or poor weather resistance when actually used may occur. .

Further, JP-A-61-28433, JP-A-61-61623 and JP-A-1-141968.
In the publications and the like, it is described that, as a group adsorbed to a pigment, a reaction product of a polycarboxylic acid and an alcohol can be used as a pigment dispersant, unlike the above polyamine structure. However, according to the experiments of the inventor, those described in these publications are low-molecular-weight carboxyl group-containing carboxylic acids, and the function of being adsorbed by the pigment is insufficient, resulting in pigment dispersibility and pigment dispersion. The storage stability and flow curation resistance of the liquid were insufficient.

[0005]

In view of the present situation, the present inventor diligently studied for the purpose of providing a pigment dispersant and a composition containing the pigment dispersant, which have solved the problems and problems existing in the prior art. As a result, the reaction product obtained by reacting a polyester component having a terminal hydroxyl group derived from a monohydric alcohol and a lactone with a carboxylic acid polymer component can be an effective dispersant suitable for the purpose. The inventors have found out and completed the present invention.

That is, according to the first aspect of the present invention, the lactone compound represented by the following general formula (2) or the hydroxycarboxylic acid having 2 to 40 carbon atoms is added to the monohydric alcohol represented by the following general formula (1). A polyester component (component A) having a hydroxyl group at the terminal and having a number average molecular weight of 100 to 10,000, which is obtained by reacting the above, an acid anhydride structural unit represented by the following general formula (3), and a carboxyl derived from an acid anhydride. Number average molecular weight 1 containing a structural unit having a group or a (meth) acrylic acid structural unit represented by the following general formula (4)
There is provided a pigment dispersant characterized by comprising a reaction product of 0-100,000 with a carboxylic acid polymer component (component B) or an alkali metal salt or ammonium salt thereof. In the present specification, (meth) acrylic acid means
Indicates acrylic acid or methacrylic acid.

[0007]

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[0008]

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[0009]

[Chemical 6]

According to a second aspect of the present invention, there is provided a coating composition containing the first pigment dispersant as a dispersant.

Further, according to a third aspect of the present invention, the first
There is provided a printing ink composition containing the pigment dispersant of (1) as a dispersant.

Hereinafter, the present invention will be described in detail. (About Component A) Component A is obtained by reacting with a monohydric alcohol represented by the above general formula (1), a lactone compound represented by the above general formula (2), or a hydroxycarboxylic acid having 2 to 40 carbon atoms. It is a polyester having a number average molecular weight of 100 to 10,000 having a hydroxyl group at the terminal obtained.

The monohydric alcohol represented by the general formula (1) includes various aliphatic groups such as methanol, ethanol, isopropanol, butanol, n-octanol, 2-ethylhexyl alcohol, lauryl alcohol and stearyl alcohol depending on the type of R. Alcohols, aromatic alcohols such as benzyl alcohol, alicyclic alcohols such as cyclohexyl alcohol, ethylene glycol monobutyl ethers such as ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, propylene glycol monoalkyl ethers Is mentioned.

Examples of the lactone compound represented by the general formula (2) which is reacted with the monohydric alcohol include ε-caprolactone, δ-valerolactone, β-methyl-δ-valerolactone, β-propiolactone and γ. -Butyrolactone, 2-methylcaprolactone, 4-methylcaprolactone and the like can be mentioned. In particular, when a lactone having a side chain is used, the resulting pigment dispersant becomes liquid,
It is advantageous in terms of workability when preparing paints and inks, and compatibility with resins for paints. These lactone compounds may be used alone or as a mixture of two or more kinds. Among lactone compounds, ε-caprolactone, 4
Particularly preferred are -methylcaprolactone, a mixture of ε-caprolactone and 4-methylcaprolactone.

2 to 2 carbon atoms reacted with a monohydric alcohol
As the 40 hydroxycarboxylic acid, glycolic acid,
Lactic acid, 2-hydroxy long-chain fatty acids such as 2-hydroxyhexanoic acid and 2-hydroxydecanoic acid, 3-hydroxy long-chain fatty acids such as 3-hydroxyhexanoic acid and 3-hydroxydecanoic acid, 12-hydroxystearic acid, etc. Examples include straight-chain and branched ones. These hydroxycarboxylic acids may be reacted alone with a monohydric alcohol, but by copolymerizing with the lactone compound,
It functions to lower the crystallinity of polylactones, improve the compatibility with resins and solvents, and lower the melting point.

The composition ratio of the hydroxycarboxylic acid to the lactone compound is preferably selected in a molar ratio of hydroxycarboxylic acid: lactone compound = 0: 100 to 60:40, and particularly preferably 10:90 to 30 :.
The range is 70. When the hydroxycarboxylic acid content is 60:40 or more, the dispersion performance is deteriorated and the adhesion of the coating film to the metal surface is deteriorated, which is not preferable.

To synthesize the component A, a raw material alcohol, lactone or further hydroxycarboxylic acid is charged into a reactor equipped with a dehydration tube and a condenser, and a ring-opening polymerization reaction is carried out under a nitrogen stream. In the synthetic reaction,
It is also possible to use a suitable dehydrating solvent such as toluene or xylene. After completion of the reaction, the solvent used for the reaction may be removed by an operation such as distillation, or may be directly reacted with the carboxylic acid polymer component (component B) in the solvent and used as a part of the product. it can.

When synthesizing the component A, it is preferable to use a polymerization catalyst. As the catalyst that can be used, tin octylate, dibutyltin oxide, dibutyltin laurate, monobutyltin oxide, organic tin compounds such as hydroxybutyl oxide, stannous oxide, tin compounds such as stannous chloride, tetra Butyl titanate, tetraethyl titanate, tetrapropyl titanate and the like can be mentioned.

The amount of catalyst used is 0.
It is preferable to select in the range of 1 to 3000 ppm. When the amount of the catalyst used is 0.1 ppm or less, the polymerization rate of the polyester becomes extremely slow, which is not preferable.
When it is 0 ppm or more, coloring of the polyester becomes severe and the stability of the product is adversely affected, which is not preferable. Particularly preferred within the above range is 1 to 100 ppm.
It is.

The temperature for synthesizing the component A varies depending on the type of raw material, the molar ratio, the type and amount of catalyst, the type and amount of solvent, and the like, but it is preferably selected in the range of 120 to 220 ° C. When the reaction temperature is 120 ° C. or lower, the reaction rate is extremely slow, and when the reaction temperature is 210 ° C. or higher, side reactions other than the addition reaction of lactones, such as decomposition of a lactone polymer into a lactone monomer and formation of a cyclic lactone dimer, are likely to occur. Carboxyl group-terminated polylactones having a target molecular weight are difficult to synthesize, and the obtained copolymer is likely to be colored, which is not preferable. Particularly preferable temperature range is 160 to 210 ° C.

When synthesizing the component A, the presence of air in the reaction system tends to cause the product to be colored, so that the reaction is preferably performed in an atmosphere of an inert gas such as nitrogen gas.

The component A can be synthesized by the above method, is a polyester copolymer having a polylactone component in its molecular chain, and is a copolymer having a carboxyl group at the terminal. The polyester portion contained in the molecular chain of the copolymer has a function of forming a three-dimensional repulsion layer around the pigment. According to the experiments of the present inventor, it was found that the number average molecular weight of the polyester portion is preferably in the range of 100 to 10,000. When the molecular weight of the polyester portion is 100 or less, a three-dimensional repulsion layer having a sufficient thickness cannot be formed, and when the molecular weight is 10,000 or more, it is not preferable in terms of compatibility with other resins and solvents.
Here, the number average molecular weight means a molecular weight converted from the following hydroxyl value.

The component A is a polyester copolymer having a polylactone component in its molecular chain as described above,
Moreover, it is a copolymer having a hydroxyl group at the terminal. According to the experiment of the present inventor, the component A has a hydroxyl value of the component A
It has been found that those within the range of 5 to 560 mgKOH / g are preferable. Here, the “hydroxyl value” means the number of mg of potassium hydroxide required to neutralize the acetic acid necessary for acetylating the free hydroxyl groups contained in 1 g of the sample.

(About Component B) Component B is represented by the acid anhydride represented by the general formula (3), the structure derived from the acid anhydride, and / or the general formula (4) ( It is a (meth) acrylic acid ester polymer containing (meth) acrylic acid. These structures may be present alone or simultaneously in the polymer, and may include other copolymerizable monomers.

The acid anhydride structural unit represented by the general formula (3) is typically a structural unit derived from a carboxylic acid anhydride having a double bond. Examples of the carboxylic acid anhydrides include fumaric acid anhydride, maleic acid anhydride, and itaconic acid anhydride. Examples of the structural unit derived from an acid anhydride include those represented by the general formula (3),
An acid anhydride or a carboxyl group may form a salt with a metal or an amine.

Other copolymerizable monomers that can be copolymerized with these carboxylic acid anhydrides having double bonds include styrene, styrene derivatives such as α-methylstyrene, (meth) acrylic acid, methyl methacrylate and methyl acrylate. , (Meth) acrylic acid, (meth) acrylic acid-
n-propyl, isopropyl (meth) acrylate, n-butyl (meth) acrylate, (meth) acrylic acid-n
-Octyl, isobutyl (meth) acrylate, (meth)
2-Ethylhexyl acrylate, cyclohexyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxyalkylene (meth) acrylate in which caprolactone is added to the hydroxyl group, ethylene oxide, (meth) acrylic acid adduct of propylene oxide, etc. (Meth) acrylic acid derivatives, allyl alcohol derivatives such as methyl vinyl ether and allyl glycol, and unsaturated monomers such as ethylene, propylene, butene, and isobutene. These other copolymerizable monomers may be used alone or as a mixture of two or more kinds. The molar ratio of the acid anhydride containing these double bonds and the polymerizable monomer to be copolymerized is preferably selected in the range of 5: 1 to 1:20.

The component B can be obtained by appropriately combining the above-mentioned monomers, and among them, particularly preferable combinations of the component B are maleic anhydride and styrene, maleic anhydride and methyl vinyl ether, and the like.

The component B can be synthesized by charging a raw material monomer mixture into a reactor equipped with a raw material dropping device and a condenser, and using a radical polymerization initiator to react the mixture in an inert gas flow. It is desirable to use a suitable reaction solvent such as toluene or xylene for the synthesis reaction. The solvent used in the reaction can be used as a part of the product by removing it by an operation such as distillation after completion of the reaction or by reacting with the component A while containing the solvent.

As the radical polymerization initiator that can be used,
Organic peroxides such as benzoyl peroxide, dibenzyl peroxide, ditertiary butyl peroxide, dicumyl peroxide, azobisisobutyronitrile, 2,2-azobis (2,4-dimethylvaleronitrile), etc. Examples thereof include azo compounds. The amount of the polymerization initiator used varies depending on the combination and ratio of the raw material monomers, the reaction temperature, the type and amount of the solvent, etc., but can be selected within the range of 0.1 to 10000 ppm with respect to the mixture of the raw material monomers.

The temperature for synthesizing the component B varies depending on the combination and ratio of the raw material monomers, the type and amount of the polymerization initiator, the type and amount of the solvent, and the like, but can be selected in the range of 40 to 200 ° C. When the temperature is 40 ° C. or lower, the reaction rate is extremely slow, and when the temperature is 200 ° C. or higher, there is a risk of reaction runaway and a (meth) acrylic acid polymer having a target molecular weight cannot be obtained due to side reactions and the like. Not preferable.

The component (B) reacts with the component (A) to form an adsorption group that is adsorbed by the pigment, and the number average molecular weight of the component (B) is preferably in the range of 100 to 100,000. If the molecular weight is 100 or less, the adsorbing group is too small to contain a sufficient carboxyl group-containing residue, so that the adsorbability to the pigment becomes insufficient, and if the molecular weight exceeds 100,000, aggregation of the pigments tends to be promoted. Both are not preferable, because they become remarkable and the molecular weight of the entire pigment dispersant increases, and the compatibility and solubility in the vehicle for paints, inks or solvents decrease. In addition, here B
The number average molecular weight of a component means the molecular weight measured by the GPC method.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION

(Method for synthesizing pigment dispersant) Next, a method for synthesizing the pigment dispersant according to the first aspect of the present invention will be described. The pigment dispersant according to the present invention is synthesized by an addition reaction between a terminal OH group of a monofunctional polyester of component A and an acid anhydride contained in component B, or a condensation reaction of a carboxyl group contained in component B. To be done. The resulting dispersant has a structure in which the A component is grafted onto the B component.

The above reaction is carried out in an inert gas stream by charging a reactor equipped with a dehydration tube and a condenser with the components A and B, an appropriate reaction solvent and, if necessary, a catalyst. At this time, a suitable dehydrating solvent such as toluene or xylene can be used. The solvent used for the reaction can be removed by an operation such as distillation after the reaction is completed, or can be used as a part of the product as it is.

The temperature of the above reaction can be selected in the range of 30 to 220 ° C. If the temperature is 30 ° C or lower, the reaction rate is extremely slow, and if it is 220 ° C or higher, decomposition of the lactone-containing polyester into monomers, formation of cyclic lactone dimer, and the like are likely to occur, and coloring of the produced copolymer is likely to occur. Therefore, neither is preferable. Particularly preferable range is 80 to 150 ° C.

The pigment dispersant obtained by the above reaction has an acid value of 5 to 1000 according to the experiments of the present inventors.
It has been found that a range of mgKOH / g is preferred. When the acid value is 5 mgKOH / g or less, the amount of carboxyl groups interacting with the pigment is too small to provide a sufficient dispersing effect, while when it exceeds 1000 mgKOH / g, the acid value is too high and the coating properties, Water-resistant or curable paints are not preferable because they reduce hot life and impair curability. The acid value of the pigment dispersant means the number of mg of potassium hydroxide required to neutralize the acid contained in 1 g of the sample.

(Method of Using Pigment Dispersant) The pigment dispersant according to the first aspect of the present invention is mixed with pigments, dyes and other additives and dispersed by a known method to prepare a coating composition and a printing ink composition. It can be used as a thing. That is, the coating composition and the printing ink composition can be obtained by mixing the solid, the dispersant, and particularly the liquid polar organic medium in any order. When used in these applications, the pigment dispersant according to the first aspect of the present invention is adsorbed by a pigment or the like, and therefore has a function of improving pigment dispersibility, mill-base fluidity, storage stability of a pigment dispersion, and the like.

Examples of pigments that can be used in combination with the pigment dispersant according to the first aspect of the present invention include inorganic pigments, organic pigments and organic dyes. Examples of the inorganic pigment include titanium oxide, zinc oxide, cadmium sulfide, yellow iron oxide, red iron oxide, yellow lead, carbon black, and the like, and organic pigments include phthalocyanines, insoluble azo pigments, azo lake pigments, and condensed polycyclic pigments ( Examples include various pigments such as slene-based, indigo-based, perylene-based, perinone-based, phthalone-based, dioxazine-based, quinacridone-based, isoindolinone-based, diketopyrrolopyrrole-based pigments).

Examples of other additives include dispersed resins and magnetic materials. Examples of the dispersion resin include alkyd resin, oil-free alkyd resin, epoxy resin, acrylic resin, urethane resin, melamine resin, guanamine resin, and urea resin. As a magnetic material,
Examples include magnetic metal organic compounds.

[0039]

EXAMPLES The present invention will be described in detail below with reference to synthesis examples, examples and application examples, but the present invention is not limited to these description examples unless it exceeds the gist. In the following description examples, “part” and “%” both mean “weight basis”.

In the following description examples, the hydroxyl value,
The acid value and the like are measured by the methods described below. (1) Hydroxyl value: based on JIS K-1557. (2) Acid value: According to JIS K-1557. (3) Method for measuring number average molecular weight of component A: Conversion from hydroxyl value was performed. (4) Method for measuring number average molecular weight of component B: By gel permeation chromatography.

[Synthesis Example 1: Synthesis of Intermediate 1] 2-Ethylhexyl alcohol 377 was placed in a 3-liter reactor equipped with a condenser, a nitrogen inlet tube, a stirrer and a thermometer.
Parts, ε-caprolactone 1623 parts, and 0.2 parts of a 5% hexane solution of tetra-n-butyl titanate were charged. While stirring the contents, the internal temperature was raised to 170 ° C. under a nitrogen gas stream, and the reaction was performed at this temperature for about 8 hours.
-Reacted until caprolactone monomer is below 1%. The product was in the form of a hard wax, the hydroxyl value was 47 mgKOH / g, and the number average molecular weight of the polyester component was 1200. Hereinafter, this is referred to as "intermediate 1".

[Synthesis Example 2: Synthesis of Intermediate 2] 226 parts of 2-ethylhexyl alcohol and ε-caprolactone 1242 were placed in the same reactor used for the synthesis of “Intermediate 1”.
Part, 4-methylcaprolactone 532 g, tetra-n-
0.2 part of a 5% hexane solution of butyl titanate was charged. While stirring the contents, under a nitrogen gas stream,
The internal temperature was raised to 170 ° C., the reaction was carried out at this temperature for about 8 hours, and the reaction was carried out until the ε-caprolactone monomer and 4-methylcaprolactone in the sample sampled from the reactor were each 1% or less. The product was a viscous liquid, the hydroxyl value was 27 mgKOH / g, and the number average molecular weight of the polyester component was 2080. Hereinafter, this is referred to as "intermediate 2".

[Synthesis Example 3: Synthesis of Intermediate 3] 118 parts of ethylene glycol monobutyl ether and ε-caprolactone 6 were placed in the same reactor used for the synthesis of "Intermediate 1".
91 parts, 4-methylcaprolactone 733 g, tetra-
0.4 parts of a 5% hexane solution of n-butyl titanate,
I prepared each. While stirring the content, the internal temperature was raised to 200 ° C. under a nitrogen gas stream, and the reaction was carried out at this temperature for about 15 hours until the acid value of the sample sampled from the reactor became 3 or less. The product was a viscous liquid, the hydroxyl value was 38 mgKOH / g, and the number average molecular weight of the polyester component was 1470. Hereinafter, this is referred to as "intermediate 3".

Example 1 Synthesis of Dispersant 1 A SMA (styrene-maleic anhydride copolymer) resin (elf atom) was placed in a reactor having a capacity of 1 liter equipped with a condenser, a nitrogen inlet tube, a stirrer and a thermometer. Manufactured by SAM
-1000, the number average molecular weight was 1000) 100 parts, and "Intermediate 1" 588 parts were charged, respectively. While stirring the contents, the internal temperature was raised to 160 ° C. under a nitrogen gas stream, the reaction was carried out at this temperature for about 8 hours, and the sample sampled from the reactor was subjected to absorption of acid anhydride (1
The reaction was continued until 820,1760 cm ^-1 ) was not observed. The product is a hard wax and has an acid value of 40 mgK.
OH / g. Hereinafter, this is referred to as "dispersant 1".

Example 2: Synthesis of Dispersant 2 100 parts of SMA resin (same as used in the synthesis of Dispersant 1) in the same reactor used to synthesize "Dispersant 1",
980.4 parts of "Intermediate 2" were charged. While stirring the contents, the internal temperature was raised to 160 ° C. under a nitrogen gas stream, the reaction was carried out at this temperature for about 8 hours, and the sample sampled from the reactor was subjected to absorption of acid anhydride (1820, The reaction was continued until 1760 cm ^-1 ) was not observed. The product is a viscous liquid with an acid value of 26.
mg KOH / g. Hereinafter, this is referred to as "dispersant 2".

Example 3: Synthesis of Dispersant 3 100 parts of SMA resin (same as that used in the synthesis of Dispersant 1) were added to the same reactor used to synthesize "Dispersant 1".
735 parts of "Intermediate 3" were charged. While stirring the contents, the internal temperature was raised to 160 ° C. under a nitrogen gas stream, the reaction was carried out at this temperature for about 8 hours, and the sample sampled from the reactor was subjected to absorption of acid anhydride (1820, The reaction was continued until 1760 cm ^-1 ) was not observed. The product is a viscous liquid with an acid value of 33m.
gKOH / g. Hereinafter, this is referred to as "dispersant 3".

Example 4: Synthesis of Dispersant 4 In the same reactor used to synthesize "Dispersant 1", a methyl vinyl ether / maleic anhydride copolymer ("VEMA A101" manufactured by Daicel Chemical Co., Ltd., Number average molecular weight is about 2000
0, copolymerization ratio 50:50, low molecular weight type methyl vinyl ether / maleic anhydride copolymer 100 parts,
633 parts of "Intermediate 1" were charged. While stirring the contents, the internal temperature was raised to 180 ° C. under a nitrogen gas stream, the reaction was performed at this temperature for about 8 hours, and the sample sampled from the reactor was subjected to absorption of acid anhydride (1820, The reaction was continued until 1760 cm ^-1 ) was not observed. The product is a hard wax and has an acid value of 4
It was 7 mgKOH / g. Hereinafter, this is referred to as "dispersant 4".
That.

[Examples 5 to 14, Comparative Examples 1 to 5: Preparation Example of Pigment Composition by Pigment Dispersant] The dispersant obtained by the method described in Example was mixed with a paint resin (polyester and acrylic resin). ), A pigment, a solvent, etc., and glass beads are further added, and the mixture is dispersed by a disperser (manufactured by Red Devil) to
The pigment composition was dispersed for a time to obtain a pigment composition in which the pigment was dispersed by a pigment dispersant. With respect to the obtained pigment composition, the fluidity of the mill base after dispersion was evaluated by the method described below. The results are shown in Table-1, Table-2 and Table-3.

(1) Millbase fluidity A: Immediately after the pigment composition is prepared, the pigment composition is visually observed, and those having good fluidity are indicated as "good" and those not dispersed are indicated as "not dispersed". did. (2) Millbase fluidity B: A pigment composition was prepared and then left standing at room temperature for 24 hours, and the pigment composition was visually observed in the same manner as in the case of A above. The display of the results was the same as in the case of A above.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

From Table-1 to Table-3, the following is clear. (1) A pigment dispersion composition prepared by using the pigment dispersant according to the present invention has excellent mill-base fluidity and storage stability of the dispersion composition (Experiment No. 1 to Experiment No. 1).
10). (2) On the other hand, the pigment dispersion composition prepared without using the pigment dispersant according to the present invention has poor dispersibility (see Comparative Examples 1 to 5).

[0054]

INDUSTRIAL APPLICABILITY The present invention has the following particularly advantageous effects, and its industrial utility value is extremely large. (1) The pigment dispersant according to the present invention improves the dispersibility of a large number of pigments in a wide range. (2) The pigment liquid composition dispersed by the pigment dispersant according to the present invention exhibits excellent mill-base fluidity. (3) The pigment liquid composition dispersed by the pigment dispersant according to the present invention exhibits excellent storage stability. (5) Since the pigment dispersant according to the present invention has a (meth) acrylic acid ester polymer component in its molecular chain, it exhibits excellent weather resistance.

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Claims (4)

[Claims] 1. A terminal obtained by reacting a monohydric alcohol represented by the following general formula (1) with a lactone compound represented by the following general formula (2) or a hydroxycarboxylic acid having 2 to 40 carbon atoms. Number average molecular weight having hydroxyl group 100 to 1
0000 polyester component (A component), an acid anhydride structural unit represented by the following general formula (3), a structural unit having a carboxyl group derived from an acid anhydride or the following general formula (4) ( A pigment dispersant comprising a reaction product with a carboxylic acid polymer component (component B) having a number average molecular weight of 100 to 100,000 containing a (meth) acrylic acid structural unit, or an alkali metal salt or ammonium salt thereof. Embedded image Embedded image Embedded image 2. The acid value of the reaction product is 5 to 1000 mgK.
The pigment dispersant according to claim 1, which is in the range of OH / g. 3. A coating composition comprising the pigment dispersant according to claim 1 as a dispersant. 4. A printing ink composition comprising the pigment dispersant according to claim 1 as a dispersant.