JPH07149855A - Production of pigment dispersant - Google Patents

Abstract

PURPOSE:To obtain a pigment dispersant useful for coating compound, not crystallizing even at a cold place or in winter, having excellent adhesivity, dispersibility and compatibility by reacting a specific isocyanate-containing compound with a prescribed polyamine in a specific ratio. CONSTITUTION:This pigment dispersant is obtained by reacting (A) an isocyanate-containing compound prepared by reaction of (i) a primary alcohol of formula I (R<1> is 1-24C hydrocarbon, etc.), (ii) a lactone compound of formula II (L and (m) are 1-10; (n) is 0-10; R<2> and R<3> are H or 1-4C alkyl), (iii) an end hydroxyl group-containing polyester derived from a hydroxycarboxylic acid such as lactic acid, having 100-10,000 number-average molecular weight and (iv) an end isocyanate group-containing compound having two isocyanate groups with (B) a polyalkylenepolyamine having 100-20,000 number-average molecular weight in the motor ratio of the component A and B of 1/1 to 400/1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispersant which improves the dispersibility of pigments in the production of paints and inks.

[0002]

2. Description of the Related Art In the production of paints and inks, the dispersibility of pigments is improved, the storage stability of paints and the like, the prevention of color separation,
Various dispersants are used for the purpose of increasing the gloss of a coating film.

For this purpose, 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, JP-A-63-197529 and JP-A-54-37082. The one reported in JP-A-48-79178 is known.

[0004]

The polyester portion of such a dispersant requires a certain molecular weight in order to form an effective barrier layer around the pigment.
The dispersant having a polyester chain obtained by ring-opening polymerization of a lactone such as caprolactone with a long-chain carboxylic acid described in 1-174939 and JP-A-63-197529 is By design, it becomes a mixture of high molecular weight polycaprolactone and unreacted carboxylic acid.

Therefore, the produced dispersant has high crystallinity and is solid at room temperature and has poor workability. When paints and inks are produced using these dispersants, they are dispersed during storage in cold regions or winter. There is a problem that the agent crystallizes in the paint and impairs the appearance of the coating film.

JP-A-54-37082 and JP-A-48-7
9178 is a dispersant using a polyester obtained by degreasing condensation of a long-chain aliphatic hydroxycarboxylic acid such as 12-hydroxystearic acid, and has a wide dispersion performance for various pigments, but in a high-concentration pigment dispersion liquid, ,
The fluidity of the dispersion and the tinting strength of paints and inks have not been sufficiently satisfactory. Further, the dispersant having such a structure has a problem that the paint or ink applied to a metal lowers the adhesion between the coating film and the metal surface.

[0007]

DISCLOSURE OF THE INVENTION As a result of intensive studies conducted by the present inventor in view of the above-mentioned problems of the prior art, the present invention has a high compatibility with various paint vehicles and is a dispersant in paint even in cold regions and winter. Does not crystallize, does not affect the appearance of the coating film, and does not impair the adhesion to the metal surface,
A method for producing a pigment dispersant having a structure excellent in dispersion performance was found.

That is, the present invention provides "(a) the following formula (I) R ¹ -OH ... (I) << R ¹ in the formula is a linear, branched or alicyclic group having 1 to 24 carbon atoms. Formula, aromatic hydrocarbon group or R- (CH ₂ CH ₂ O)
_n- <R represents an aliphatic alkyl group, n represents a substituent represented by 1 to 3> and a primary alcohol component represented by the following formula (II)

[Chemical 2] (II) << L and m are 1 to 10, n is carbon number 0 to 10,
R ² and R ³ are hydrogen or a lactone compound represented by an aliphatic alkyl group having 1 to 4 carbon atoms and a number average molecular weight 100 to 10,000 polyester having a hydroxyl group at the terminal derived from a hydroxycarboxylic acid, and 1 molecule A compound having an isocyanate group at the terminal by the reaction with an isocyanate compound having two or more isocyanate groups (NCO-), and (b) a number average molecular weight of 100 to 20
000 polyamine compound, the above-mentioned (a) and (b) are reacted in a molar ratio of 1: 1 to 400: 1.

The component (a) in the present invention is a component composed of a primary alcohol component, a hydroxycarboxylic acid, a lactone compound and a polyvalent isocyanate, and has an isocyanate group at the terminal. The polyester portion has a number average molecular weight of 100 to 10,000. The polyester part has the function of forming a three-dimensional repulsion layer around the pigment,
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 the molecular weight is 1
When it is 0000 or more, there is a problem in compatibility with resins and solvents.

The primary alcohols include methanol, ethanol, isopropanol, butanol and n-.
Various aliphatic, alicyclic and aromatic alcohols such as octanol, 2-ethylhexyl alcohol, lauryl alcohol, stearyl alcohol, benzyl alcohol and cyclohexanol can be used.

By copolymerizing hydroxycarboxylic acid, it has the functions of lowering the crystallinity of polylactones, improving the compatibility with resins and solvents, and lowering the melting point. As these hydroxycarboxylic acids, linear or branched ones such as 2-hydroxypropionic acid and 12-hydroxystearic acid can be used.

As the lactone compound, lactones such as ε-caprolactone, δ-valerolactone, β-methyl-δ-valerolactone, β-propiolactone and γ-butyrolactone can be used.

The composition ratio of the hydroxycarboxylic acid to the lactone compound is a molar ratio of hydroxycarboxylic acid: lactone compound = 1: 99 to 60:40, preferably 1
The range is 0:90 to 30:70. When the content of hydroxycarboxylic acid is 1:99 or less, the effect of copolymerizing hydroxycarboxylic acid is not observed, and when the content of hydroxycarboxylic acid is 60:40 or more, the dispersibility is decreased,
The adhesion of the coating film to the metal surface is likely to decrease.

In the general formula (II), L and m are 1 to 10, n is a carbon number of 0 to 10, R ² and R ³ are hydrogen, or an aliphatic alkyl group having a carbon number of 1 to 4, and all of them are It depends on the lactone compound used.

Isocyanates include various types of isocyanate having two or more isocyanate groups in the molecule, tolylene diisocyanate (TDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HMDI), 4,4'-phenylmethane diisocyanate (MDI). , Hydrogenated MDI, and their trimers (burette-bonded type, adduct type, nurate type) can be used. Next, a method for producing the dispersant will be described. The component (a) is synthesized by charging a primary alcohol, a hydroxycarboxylic acid, and a lactone into a reactor having a dehydration tube and a condenser, and dehydrating and polymerizing the mixture in a nitrogen stream. Esterification temperature is 150 ° C to 220
C., preferably in the range of 170.degree. C. to 210.degree. When the reaction temperature is 150 ° C or lower, the reaction rate is very slow.
At 20 ° C or higher, decomposition or coloring of the reaction product is likely to occur.

As the esterification catalyst, tin octylate,
Organotin compounds such as dibutyltin oxide, dibutyltin laurate and monobutyltin hydroxybutyl oxide, tin compounds such as stannous oxide and stannous chloride, tetrabutyl titanate, tetraethyl titanate and tetrapropyl titanate can be used.

The amount of catalyst used is 0.1 PPM to 1000 P
PM, preferably 1 PPM to 300 PPM. When the amount of the catalyst is 1000 PPM or more, the resin is severely colored, which adversely affects the stability of the product.

On the contrary, when the amount of the catalyst used is less than 1 PPM, the polymerization rate of the polyester becomes extremely slow, which is not preferable. In addition, since there is a tendency for coloration when reacted in the presence of air, it is desirable to react in an inert atmosphere such as a nitrogen stream.

After the polyester synthesis is completed, the terminal OH of the polyester is reacted with an isocyanate compound. In this case, the isocyanate compound is the terminal O of the polyester.
By reacting with H, an appropriate amount of one isocyanate in the molecule of the isocyanate compound is reacted to synthesize a prepolymer of component (a) having an isocyanate group at the terminal.

Next, the number average molecular weight of the component (b) is 100 to 2
The target pigment dispersant is obtained by reacting 0000 polyalkylene polyamine compounds with component (a) and component (b) in a molar ratio of 1: 1 to 250: 1. In the reaction, the component (a) and the component (b) are charged into a reactor having a dehydration tube and a condenser, and a urethanization reaction is carried out.

The temperature is from 10 ° C to 100 ° C, preferably
It is performed in the range of 30 to 70 ° C. When the reaction temperature is 10 ° C. or lower, the reaction rate is slow, and when the reaction temperature is 70 ° C. or higher, the reaction is likely to proceed rapidly and coloring easily occurs. The reaction proceeds even without a catalyst, but a known catalyst such as dibutyltin dilaurate can be used as the urethanization reaction catalyst.

The amount of the catalyst used is 0.1 PPM to 1000 P
PM, preferably 1 PPM to 100 PPM. When the amount of the catalyst is 1000 PPM or more, the resin is severely colored, which adversely affects the stability of the product.

The reaction can be carried out in a state of being dissolved in a suitable solvent such as toluene, xylene and MIBK. These solvents can be removed after the reaction is completed, or can be used as they are as a dispersant. On the contrary, when the amount of the catalyst used is 1 PPM or less, the effect of adding the catalyst is not recognized.

When the molar ratio of the component (a) to the component (b) is 1: 1 or less, the amount of the polyester portion forming the three-dimensional repulsion layer is too small, and sufficient performance as a dispersant may be exhibited. Can not. On the contrary, the molar ratio of component (a) and component (b) is 40
When it is 0: 1 or more, the polyester portion is too much and the amount of the remaining amino groups becomes too small, resulting in a decrease in the adsorption performance to the pigment, which does not give sufficient performance as a dispersant.

The above pigment dispersants include inorganic pigments such as titanium oxide, zinc oxide, cadmium sulfide, yellow iron oxide, red iron oxide, yellow lead, carbon black, phthalocyanines, insoluble azo pigments, azo lake pigments, and condensed polycyclic compounds. It has excellent pigment dispersibility with respect to pigments (slene-based, indigo-based, perylene-based, perinone-based, phthalone-based, dioxazine-based, quinacridone-based, isoindolinone-based, diketopyrrolopyrrole-based pigments).

[0026]

The pigment dispersant of the present invention will be described below with reference to examples, but the present invention is not limited thereto. All parts in the examples indicate parts by weight.

Example 1 <Intermediate 1> Condenser, nitrogen inlet tube, agitator,
In a 2 liter reactor equipped with a thermometer, 260 parts of 2-ethylhexyl alcohol, 1305 parts of ε-caprolactone,
Charge 225 parts of 12-hydroxystearic acid and 0.15 part of tetrabutyl titanate, and 170 ° C under a nitrogen stream.
After dehydration condensation for 5 hours, the temperature is raised to 205 ° C and the acid value is 2KO.
The reaction was continued until it became Hmg / g or less. The polycaprolactone OH value of the obtained intermediate was 58.6 KOHmg / g.
Met.

<Intermediate 2> Condenser, nitrogen introducing pipe,
In a 2-liter reactor equipped with a stirrer and a thermometer, 130 parts of 2-ethylhexyl alcohol, 1145 parts of ε-caprolactone, 225 parts of 12-hydroxystearic acid,
Charge 0.15 part of tetrabutyl titanate, dehydrate and condense at 170 ° C. for 5 hours under a nitrogen stream, and raise the temperature to 205 ° C.
The reaction was continued until the acid value became 2 KOHmg / g or less. The polycaprolactone OH value of the obtained intermediate was 38.7.
It was KOH mg / g.

<Intermediate 3> Condenser, nitrogen introducing pipe,
In a 2 liter reactor equipped with a stirrer and a thermometer, 130 parts of 2-ethylhexyl alcohol, 1178 parts of ε-caprolactone, 225 parts of 12-hydroxystearic acid,
Charge 0.15 part of tetrabutyl titanate, dehydrate and condense at 170 ° C. for 5 hours under a nitrogen stream, and raise the temperature to 205 ° C.
The reaction was continued until the acid value became 2 KOHmg / g or less. The obtained intermediate has a polycaprolactone OH value of 28.3.
It was KOH mg / g.

<Intermediate 4> Condenser, nitrogen introducing pipe,
A 2 liter reactor equipped with a stirrer and a thermometer was charged with 243 parts of diethylene glycol monobutyl ether, 957 parts of ε-caprolactone, 300 parts of lactic acid and 0.15 part of tetrabutyl titanate, and the mixture was heated at 170 ° C. under a nitrogen stream at 5 ° C. for 5 hours.
After dehydration condensation for an hour, the temperature is raised to 205 ° C and the acid value is 2 KOH.
The reaction was continued until it became less than mg / g. The polycaprolactone OH value of the obtained intermediate was 28.3 KOHmg / g.

<Intermediate 5> Condenser, nitrogen introducing pipe,
In a 2 liter reactor equipped with a stirrer and a thermometer, 94 parts of benzyl alcohol, 1106 parts of ε-caprolactone,
300 parts of lactic acid and 0.15 part of tetrabutyl titanate were charged, and after dehydration condensation at 170 ° C. for 5 hours under a nitrogen stream, 20
The temperature was raised to 5 ° C., and the reaction was carried out until the acid value became 2 KOHmg / g or less. Obtained intermediate polycaprolactone O
The H value was 28.3 KOHmg / g.

<Dispersant 1> Condenser, nitrogen inlet tube,
2 liter reactor equipped with agitator and thermometer
174 parts of 100 was charged, and then 957 parts of Intermediate 1 was charged at a reaction temperature of 60 ° C. to synthesize a prepolymer having an isocyanate terminal. Then, 143 parts of polyethyteneimine (sp200 manufactured by Nippon Shokubai Co., Ltd.) was added, and the reaction was continued until the residual isocyanate was 0.1% or less.

<Dispersant 2> Condenser, nitrogen introducing pipe,
2 liter reactor equipped with agitator and thermometer
174 parts of 100 were charged, and then 1450 parts of Intermediate 2 were charged at a reaction temperature of 60 ° C. to synthesize a prepolymer having an isocyanate terminal. Then, 143 parts of polyethyteneimine (sp200 manufactured by Nippon Shokubai Co., Ltd.) was added, and the reaction was continued until the residual isocyanate was 0.1% or less.

<Dispersant 3> Condenser, nitrogen inlet tube,
2 liter reactor equipped with agitator and thermometer
174 parts of 100 was charged, and then 1980 parts of Intermediate 3 was charged at a reaction temperature of 60 ° C. to synthesize a prepolymer having an isocyanate terminal. Then, 143 parts of polyethyteneimine (sp200 manufactured by Nippon Shokubai Co., Ltd.) was added, and the reaction was continued until the residual isocyanate was 0.1% or less.

<Dispersant 4> A synthetic method similar to that of Dispersant 1 is used, but 957 parts of Intermediate 1 is used as an isocyanate and IP is used.
222 parts of DI, polyethyleneimine (Nippon Catalyst sp2
00) 143 parts were used.

<Dispersant 5> A synthetic method similar to that of Dispersant 1 is used, but 957 parts of Intermediate 1 and IP as an isocyanate are used.
222 parts of DI, polyethyleneimine (Nippon Catalyst sp2
00) 286 parts were used.

<Dispersant 6> The same synthetic method as that of Dispersant 1 is used, but 1450 parts of Intermediate 2 is used as an isocyanate.
222 parts of PDI, polyethyleneimine (Nippon Catalyst sp
200) 143 parts were used.

<Dispersant 7> The same synthetic method as in Dispersant 1 is used, but 1450 parts of Intermediate 2 is used as an isocyanate.
222 parts of PDI, polyethyleneimine (Nippon Catalyst sp
200) 286 parts were used.

<Dispersant 8> The same synthetic method as that for Dispersant 1 is used, but 1982 parts of Intermediate 3 are used as an isocyanate.
222 parts of PDI, polyethyleneimine (Nippon Catalyst sp
200) 286 parts were used.

<Dispersant 9> The same synthetic method as for Dispersant 1 is used, except that 963.9 parts of Intermediate 4, 222 parts of IPDI as an isocyanate, polyethyleneimine (Nippon Catalyst s
286 parts were used.

<Dispersant 10> The same synthetic method as for Dispersant 1 is used, except that 1516 parts of Intermediate 5 and 222 parts of IPDI as an isocyanate, polyethyleneimine (Nippon Catalyst s
p200) 143 parts were used.

<Dispersant 11> 12.7 parts of Dispersant 1 was dissolved in 100 CC of tetrahydrofuran, and 2.5 parts of dimethylsulfate was added and reacted. After the reaction was completed, the solvent was removed to obtain Dispersant 11. [Application Example 1] Titanium oxide (Taipaque CR made by Ishihara Sangyo
95: C.I. I-Pigment White 6) 70
Parts, 1 part of dispersant 1, 14.5 parts of xylene, 14.5 parts of butyl cellosolve acetate, and 100 parts of glass beads were dispersed by a disperser (manufactured by Red Devil Co.) for 30 minutes.
The dispersed paste showed good fluidity and showed fluidity even after 1 week.

[Application Example 2] Carbon black (Mitsubishi Kasei MA-100: C. I-Pigment Black)
7) 50 parts, dispersant 24 parts, xylene 23 parts, butyl cellosolve acetate 23 parts, and glass beads 100 parts were dispersed by a disperser (manufactured by Red Devil Co.) for 30 minutes. The dispersed paste showed good fluidity and showed fluidity even after 1 week.

[Application Example 3] Phthalocyanine Blue (Chromofine Blue 4920: CI-manufactured by Dainichiseika Kogyo Co., Ltd.)
Pigment Blue 15: 3) 45 parts, dispersant 3
4 parts, xylene 25.5 parts, butyl cellosolve acetate 25.5 parts, and glass beads 100 parts were dispersed by a disperser (manufactured by Red Devil Co.) for 1 hour. The dispersed paste showed good fluidity and showed fluidity even after 1 week.

[Application Example 4] Phthalocyanine Green (Chromophine Green 5310, manufactured by Dainichiseika Co., Ltd .: C.I.
I-Pigment Green 7) 45 parts, dispersant 4
4 parts, xylene 25.5 parts, butyl cellosolve acetate 25.5 parts, and glass beads 100 parts were dispersed by a disperser (manufactured by Red Devil Co.) for 1 hour. The dispersed paste showed good fluidity and showed fluidity even after 1 week.

[Application Example 5] Benzimidazolone Yellow (Chromofine Yellow 2080 manufactured by Dainichi Seika Kogyo:
C. I-Pigment Yellow 154) 30
Parts, dispersant 52 parts, xylene 34 parts, butyl cellosolve acetate 34 parts, and glass beads 100 parts were dispersed with a disperser (manufactured by Red Devil Co.) for 30 minutes. The dispersed paste showed good fluidity and showed fluidity even after 1 week.

[Application Example 6] Yellow iron oxide (manufactured by Titanium Industry)
Mapico Elo LLXLO: C.I. I-Pigment Y
ellow42) 70 parts, dispersant 6 1 part, xylene 1
4.5 parts, 14.5 parts of butyl cellosolve acetate, and 100 parts of glass beads were dispersed by a disperser (manufactured by Red Devil Co.) for 30 minutes. The dispersed paste showed good fluidity and showed fluidity even after 1 week.

[Application 7] Bengara (C.I-Pigm)
ent Red 101) 70 parts, dispersant 7 2 parts, xylene 14 parts, butyl cellosolve acetate 14 parts, and glass beads 100 parts were dispersed by a disperser (manufactured by Red Devil Co.) for 30 minutes. The dispersed paste showed good fluidity and showed fluidity even after 1 week.

[Application Example 8] Quinacridone (Chimo Fine Red 6820, manufactured by Dainichiseika Co., Ltd .: C-I-Pigm)
ent Violet 19) 30 parts, dispersant 8 4 parts,
MIBK 33 parts, butyl cellosolve acetate 33 parts,
100 parts of glass beads were dispersed by a disperser (manufactured by Red Devil Co.) for 30 minutes. The dispersed paste showed good fluidity and showed fluidity even after 1 week.

[Application Example 9] Brilliant Carmine 6B
(Dainippon Ink and Chemicals Inc. Shimla Brilliant Carmine 6B 236: CI Pigment Red
57: 1) 40 parts, dispersant 9 5 parts, MIBK 27.5
Part, butyl cellosolve acetate 27.5 parts, and glass beads 100 parts are dispersed with a disperser (manufactured by Red Devil Co.) 30
Minutely dispersed. The dispersed paste showed good fluidity and showed fluidity even after 1 week.

[Application Example 10] Disazo Yellow (Seika Fast Yellow 2300 manufactured by Dainichi Seika Kogyo: CI-
Pigment Yellow 12) 30 parts, dispersant 1
04 parts, MIBK 33 parts, butyl cellosolve acetate 33 parts, and glass beads 100 parts were dispersed by a disperser (manufactured by Red Devil Co.) for 30 minutes. The dispersed paste showed good fluidity and showed fluidity even after 1 week.

[Application Example 11] Brilliant Carmine 6B
(Dainippon Ink and Chemicals Inc. Shimla Brilliant Carmine 6B 236: CI Pigment Red
57: 1) 40 parts, dispersant 115 parts, MIBK27.
Disperse 5 parts, 27.5 parts of butyl cellosolve acetate and 100 parts of glass beads with a disperser (manufactured by Red Devil) 3
Dispersed for 0 minutes. The dispersed paste showed good fluidity and showed fluidity even after 1 week. [Comparative Example] <Intermediate 6> Condenser, nitrogen inlet tube, agitator,
A 2 L reactor equipped with a thermometer was charged with 130 parts of 2-ethylhexyl alcohol, 1370 parts of caprolactone monomer and 0.15 part of tetrabutyl titanate, and reacted under a nitrogen stream at 170 ° C until residual caprolactone was 1% or less. . Obtained intermediate polycaprolactone O
The H value was 38.5 KOHmg / g.

[Dispersant 12] A synthetic method similar to that of Dispersant 1 is used, except that 1457 parts of Intermediate 6 and 222 parts of IPDI as an isocyanate, polyethyleneimine (Nippon Catalyst s
p200) 143 parts were used.

[Application 12] Carbon black (Mitsubishi Kasei MA-100: CI Pigment Blac)
k 7) 50 parts, dispersant 124 parts, xylene 23 parts,
Butyl cellosolve acetate 23 parts, glass beads 10
0 part was dispersed with a disperser (manufactured by Red Devil Co.) for 30 minutes. The dispersed paste showed good flowability.

[Application Example 13] Application Example 1 and Application Example 12
The pigment paste prepared in 1 above was made into a paint with the composition shown in Table 1, and the surface glossiness (60 degrees) was measured immediately after the coating film was formed and after being left at a low temperature (5 degrees, 10 days).

Table 1 Composition Paint formulation 1 Paint formulation 2 Alkyd resin * 1) 38 38 Pigment paste (application example 2) 20 Pigment paste (application example 12) 20 Solvent Xylene 10.3 10.3 Butyl Cellosolve 10.3 10.3 Acetate leveling agent * 2) 0.4 0.4 Melamine resin * 3) 10 10 Immediately after compounding Gloss 95 90 After low temperature test * 4) Gloss 94 75 * 1) Oil-free alkyd resin manufactured by Dainippon Ink and Chemicals
M6005-60 * 2) Monsanto leveling agent Modaflow * 3) Dainippon Ink & Co., Inc. Butylated melamine resin Superbeckamine J820-60 * 4) Leave at 5 ° C for 10 days Baking conditions are 150 ° C x 30 minutes.

From the results shown in Table 1, when the pigment dispersant having a polycaprolactone chain obtained by copolymerizing a hydroxycarboxylic acid is used, the gloss is not decreased even after being left at a low temperature, and it is extremely effective for preparing a coating. I understand. (Below margin)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C09C 3/10 PCF C09D 17/00 PUJ

Claims (8)

[Claims] 1. (a) Formula (I) R ¹ —OH (I) << R ¹ in the formula is a linear, branched, alicyclic or aromatic group having 1 to 24 carbon atoms. Group hydrocarbon group or R- (CH ₂ CH ₂ O)
_n- <R represents an aliphatic alkyl group, n represents a substituent represented by 1 to 3> and a primary alcohol component represented by the following formula (II) (II) << L and m are 1 to 10, n is carbon number 0 to 10,
R ² and R ³ are hydrogen or a lactone compound represented by an aliphatic alkyl group having 1 to 4 carbon atoms and a number average molecular weight 100 to 10,000 polyester having a hydroxyl group at the terminal derived from a hydroxycarboxylic acid, and 1 molecule A compound having an isocyanate group at the terminal by the reaction with an isocyanate compound having two or more isocyanate groups (NCO-), and (b) a number average molecular weight of 100 to 20
000 polyalkylene polyamine compound, the above-mentioned (a) and (b) are reacted in a molar ratio of 1: 1 to 400: 1. 2. The content of hydroxycarboxylic acid in the polyester is 0.1% by weight to 30% by weight.
A method for producing the pigment dispersant described. 3. The method for producing a pigment dispersant according to claim 1, wherein the polyamine compound (b) is polyethyleneimine. 4. The method for producing a pigment dispersant according to claim 1, wherein a part of the amino groups of the polyamine compound (b) is a quaternary ammonium salt. 5. The hydroxycarboxylic acid is lactic acid, 12-
Hydroxystearic acid, ricinoleic acid, ricinoleic acid, castor oil fatty acid, hydrogenated castor oil fatty acid, δ-hydroxyvaleric acid, ε-hydroxycaproic acid, P-hydroxyethyloxycarboxylic acid, 2-hydroxynaphthalene-3-carboxylic acid, 2- Hydroxynaphthalene-6-carboxylic acid, 2,2-dimethylolpropionic acid, 2,2
-Dimethylolvaleric acid, 2,2-dimethylolpentanoic acid, hydroxypivalic acid, 11-oxyhexadecanoic acid, 2-oxidedecanoic acid, lactic acid, glycolic acid, malic acid, tartaric acid, gluconic acid, glyceric acid, mevalonic acid The method for producing a pigment dispersant according to claim 1, wherein the pigment dispersant is at least one. 6. A dispersion liquid containing the dispersant according to claim 1 as a dispersant for an organic solvent-based dispersion liquid in which fine solids are dispersed. 7. A coating composition comprising the dispersion liquid according to claim 6. 8. A printing ink comprising the dispersion according to claim 6.