JP7104374B2 - Non-aqueous dispersant and non-aqueous dispersion composition - Google Patents

Description

The present invention relates to a dispersant capable of imparting excellent pigment dispersibility and thixotropic properties in a non-aqueous solvent, and a non-aqueous dispersion composition containing the dispersant.

Non-aqueous dispersion compositions in which organic pigments or inorganic pigments are dispersed in a non-aqueous solvent are used in paints, printing inks, resists for color filters, etc., and by dispersing the pigments in fine particles, they have high coloring power. It has a vivid color tone. However, organic pigments and pigments such as carbon black, which have poor dispersion stability, aggregate again even if they are dispersed in fine particles, causing a decrease in color tone and an increase in viscosity. Therefore, a dispersant is used to stabilize the dispersed state.

Furthermore, in recent years, since highly fine-grained pigments have been used, the surface energy of the pigments has become higher, and in many cases, conventional pigment dispersants do not provide sufficient viscosity reduction and dispersion stability, resulting in finer pigment dispersion. Dispersants suitable for the above have been developed. For example, as a dispersant for easily dispersing and stabilizing these pigments having poor dispersion stability, a dispersant containing an acidic functional group and a benzoisoindole derivative as in Patent Document 1 or a pigment affinity as in Patent Document 2. Dispersants having a high perylene skeleton have been reported, and have achieved high dispersion stability with respect to organic pigments and carbon black and a decrease in the viscosity of the composition.

However, when these dispersants are used, the thixotropy tends to decrease as the viscosity of the composition decreases. In paint and ink applications, problems such as sagging after coating occur if the composition does not have appropriate thixotropy. Therefore, the composition is often given thixotropy by using a viscosity modifier and a thixotropic agent in combination with the dispersant (Patent Documents 3 and 4).

JP-A-2009-57477 JP-A-2014-141635 JP-A-2002-146336 JP-A-2018-62556

When these additives are used in combination, if they are incompatible with each other, dispersion may be poor, and it is necessary to optimize the combination of additives. Further, since the suitable dispersant differs depending on the pigment type to be dispersed, it is necessary to select the optimum viscosity adjusting agent and thixotropic agent to be used each time.

Therefore, there has been a demand for a dispersant capable of imparting both dispersibility and thixotropy effects, which can prevent poor dispersion due to inconsistency in compatibility when the combination of additives is changed.

The present invention has been made in view of such circumstances, and the problem to be solved is to impart dispersibility and thixotropy, in which dispersion failure due to inconsistency of compatibility when the combination of additives is changed is unlikely to occur. The purpose is to provide a possible dispersant.

As a result of diligent studies to solve the above problems, the present inventors have found that dispersibility and thixotropic properties can be imparted by using a copolymer composed of a specific component as a dispersant, and the present invention has been made. Has been completed.

(式(2)において、R³は炭素数1～15の炭化水素基を示す。)
That is, the present invention relates to the following (1) and (2).
(1) A non-aqueous pigment dispersant that disperses pigments in a non-aqueous solvent.
It is composed of a copolymer of the following monomer (a) and the following monomer (b), and the composition ratio of the monomer (a) to the monomer (b) ((a): (b). ) Is 40:60 to 90:10 in mole%, and the weight average molecular weight of the copolymer is 5,000 to 50,000.

Monomer (a)
Polyoxyalkylene derivative represented by the formula (1)

R ¹ O (AO) _n R ² (1)

(In equation (1)
R ¹ indicates a hydrocarbon group having 1 to 4 carbon atoms.
R ² represents an unsaturated hydrocarbon group with 3-4 carbon atoms with one double bond.
AO indicates one or more oxyalkylene groups having 2 to 3 carbon atoms,
n is the average number of moles of oxyalkylene group added and represents a real number from 1 to 100. )

Monomer (b)

N-substituted maleimide represented by equation (2)

(In formula (2), R ³ represents a hydrocarbon group having 1 to 15 carbon atoms.)

(2) The non-aqueous solvent contains a pigment, a non-aqueous solvent and the non-aqueous pigment dispersant according to claim 1, and the content of the non-aqueous solvent is 10 to 1000 parts by mass with respect to 100 parts by mass of the pigment. A non-aqueous dispersion composition, characterized in that the content of the aqueous pigment dispersant is 1 to 100 parts by mass.

According to the present invention, it is possible to provide a dispersion composition having dispersibility and thixotropy, which is less likely to cause dispersion failure due to inconsistency in compatibility when the combination of additives is changed.

Hereinafter, embodiments of the non-aqueous pigment dispersant (hereinafter, referred to as non-aqueous dispersant) and the non-aqueous dispersion composition of the present invention will be sequentially described.

(Non-aqueous dispersant)
The dispersant of the present invention contains the monomer (a) and the monomer (b) as essential constituent units and (c) the monomer as an arbitrary constituent unit, and has a weight average molecular weight of 5,000 to 50. It is characterized by being composed of 000 copolymers.

The monomer (a) is a polyoxyalkylene derivative represented by the formula (1).
R ¹ O (AO) _n R ² (1)

In the formula (1), R ¹ represents a hydrocarbon group having 1 to 4 carbon atoms, and may be in either a linear form or a branched form. Examples of R ¹ include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group and the like, and among them, methyl group, ethyl group and propyl group are preferable. , Butyl group, more preferably methyl group or butyl group, particularly preferably butyl group.

R ² represents an unsaturated hydrocarbon group having 3 to 4 carbon atoms having one double bond, and examples thereof include an allyl group and a metalyl group, and an allyl group is preferable.

AO represents an oxyalkylene group having 2 to 3 carbon atoms, and the oxyalkylene group may be in either a linear form or a branched form. Further, the AO may be one type or two types. When there are two types of AO, the addition form may be random or block.

Examples of the AO include an oxyethylene group and an oxypropylene group. From the viewpoint of dispersibility, the oxyethylene group can be added alone, or two types, the oxyethylene group and the oxypropylene group, can be added randomly. It is more preferable to randomly add two types, an oxyethylene group and an oxypropylene group. The composition ratio of the oxyethylene group to the oxypropylene group is preferably mol%, oxyethylene group: oxypropylene group = 10: 90 to 90:10, more preferably 25:75 to 75:25, and 40:60 to 40. 60:40 is even more preferred.

n is the average number of moles of oxyalkylene group AO added and represents a real number from 1 to 100. From the viewpoint of dispersibility, the average number of moles of AO added is preferably 5 to 50, more preferably 20 to 40. When n exceeds 100, the viscosity becomes high and it becomes difficult to handle.

The polyoxyalkylene derivative of the monomer (a) may have an unsaturated hydrocarbon group introduced into the polyoxyalkylene monoalkyl ether or a hydrocarbon group introduced into the polyoxyalkylene monoalkenyl ether. That is, after addition polymerization of an alkylene oxide having 2 to 3 carbon atoms to an alcohol having a hydrocarbon group having 1 to 4 carbon atoms, monohalogenated unsaturated hydrocarbon having an unsaturated hydrocarbon group having 3 to 4 carbon atoms A polyoxyalkylene derivative can be obtained by an etherification reaction with hydrogen. Alternatively, after addition-polymerizing an alkylene oxide having 2 to 3 carbon atoms with an alcohol having an unsaturated hydrocarbon group having 3 to 4 carbon atoms, a monohalogenated hydrocarbon having a hydrocarbon group having 1 to 4 carbon atoms can be used. A polyoxyalkylene derivative can be obtained by the etherification reaction of the above.

In addition, the monomer (a) can be used alone or in combination of two or more.

(R³は炭素数1～15の炭化水素基を示す。)で表されるN-置換マレイミドである。 Monomer (b) is given by equation (2)

(R ³ indicates a hydrocarbon group having 1 to 15 carbon atoms.) It is an N-substituted maleimide represented by.

R ³ is usually an aliphatic hydrocarbon group and an aromatic hydrocarbon group, more preferably an aromatic hydrocarbon group. The carbon number of R ³ is preferably 5 to 12, more preferably 6 to 10, and particularly preferably 6 carbon atoms. Further, as the aromatic hydrocarbon group, a substituted phenyl group or a naphthyl group substituted with a phenyl group, a halogen atom, an alkyl group or a carboxy group is particularly preferable. Examples of the N-substituted maleimide having an aromatic hydrocarbon group include N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-carboxyphenylmaleimide, N-naphthylmaleimide and the like, and dispersibility and thixotropic property. N-Phenylmaleimide is preferable from the viewpoint of.

In addition, the monomer (b) can be used alone or in combination of two or more.

In order to obtain the copolymer of the present invention, the above-mentioned monomers (a) and (b) may be polymerized. From the viewpoint of dispersibility and thixotropy, the compounding ratio of each monomer is such that the monomer (a) and the monomer (b) are in molar% (a): (b) = 40: 60 to 90:10. However, it is preferably 50:50 to 90:10, more preferably 65:35 to 85:15, and even more preferably 70:30 to 85:15. If it is out of the above range, the dispersibility is lowered.

Further, the copolymer of the present invention may contain a monomer (a) and a monomer (c) copolymerizable with the monomer (b), if desired. Examples of the monomer include styrene, vinyl acetate, vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, acrylonitrile, methacrylonitrile, acrylamide, and methacrylamide. , Isobutylene, diisobutylene, vinylcyclohexane and other compounds having an ethylenically unsaturated bond, and maleic acid compounds such as maleic anhydride, maleic acid, maleate and maleic acid ester. From the viewpoint of thixotropy, it is preferable to use a maleic acid-based compound, and more preferably maleic anhydride.

In addition, the monomer (c) can be used alone or in combination of two or more.

The content of the monomer (c) is 0 to 100 mol parts when the total amount of the monomer (a) and the monomer (b) is 100 mol parts from the viewpoint of dispersibility and thixotropic property. Preferably, 30 to 80 mol parts are more preferable, and 40 to 60 mol parts are even more preferable.

Further, the polymerization type of the copolymer of the present invention can be carried out by a known method such as solution polymerization or bulk polymerization, and is not particularly limited. That is, the polymerization reaction can be carried out in the absence of a solvent or in the presence of a solvent, but when the polymerization reaction is carried out in the presence of a solvent, water; alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol;
Ketones such as acetone and methyl ethyl ketone; cyclic ethers such as tetrahydrofuran and dioxane, aliphatic hydrocarbons such as n-hexane, 2-ethyl hexane and methylcyclohexane, aromatic hydrocarbons such as toluene and xylene, etc. Can be used, and toluene and methylcyclohexane are preferably used. When the total mass of the monomers (a), (b) and (c) is 100% by mass, the amount of the solvent used is usually 1 to 50% by mass, preferably 5 to 30% by mass. The solvent used in the reaction can be removed by an operation such as distillation, or can be used as it is as a part of the product. The solution polymerization can be carried out by a batch method or a continuous method.

Examples of the polymerization initiator include peroxide-based initiators such as benzoyl peroxide, azo-based polymerization initiators such as 2,2'-azobis (isobutyric acid) dimethyl, and persulfate-based initiators such as ammonium persulfate and sodium persulfate. Can be mentioned. Further, if necessary, a chain transfer agent may be used in combination. The polymerization temperature is usually 50 to 130 ° C, preferably 60 to 90 ° C.
The polymerization time is usually 5 to 25 hours, preferably 5 to 10 hours.

From the viewpoint of dispersibility, it is preferable to use an azo-based polymerization initiator, and 2,2'-azobis (isobutyric acid) dimethyl is particularly preferable. The amount of the azo-based initiator used is usually 1 to 10 mol%, preferably 2 to 5 mol%, based on the total mass of the monomer.

In addition, a chain transfer agent can be used if desired. Examples of the chain transfer agent include dodecyl mercaptan, α-methylstyrene dimer, and the like, and the amount of the chain transfer agent used is usually 1 to 20 mol% with respect to the total mass of the monomer. The chain transfer agent may be used alone or in combination of two or more.

The weight average molecular weight (Mw) of the copolymer is 5,000 or more and 50,000 or less, more preferably 10,000 or more and 40,000 or less, and further preferably 30,000 or more and 40,000 or less. .. When Mw exceeds 50,000, the viscosity becomes high and it becomes difficult to handle. In the present specification, the weight average molecular weight means the weight average molecular weight in terms of standard polyethylene glycol by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a developing solvent.

(Non-aqueous dispersion composition)
The non-aqueous dispersion composition of the present invention contains a non-aqueous dispersant, a pigment and a non-aqueous solvent.

The content of the non-aqueous dispersant is preferably 1 to 100 parts by mass, more preferably 5 to 50 parts by mass, and further preferably 10 to 30 parts by mass with respect to 100 parts by mass of the pigment. If the content of the non-aqueous dispersant is less than 1 part by mass, sufficient dispersibility may not be obtained, and even if the content exceeds 100 parts by mass, the effect commensurate with the content may not be obtained. ..

Examples of the pigment contained in the non-aqueous dispersion composition of the present invention include organic pigments and inorganic pigments.

Examples of organic pigments include azo-based, diazo-based, condensed azo-based, thioindigo-based, induslon-based, quinacridone-based, anthraquinone-based, benzoimidazolone-based, penylene-based, phthalocyanine-based, anthrapyridine-based, and dioxazine-based pigments. Can be mentioned. Examples of inorganic pigments include titanium oxide, zinc sulfide, lead white, zinc flower, lithobon, antimony white, basic lead sulfate, basic lead silicate, barium sulfate, calcium carbonate, gypsum, silica, iron black, and titanium black. , Cobalt Violet, Vermilion, Molybdenum Orange, Lead Tan, Bengala, Yellow Lead, Cadmium Yellow, Zinc Chromate, Yellow Oaker, Chromium Oxide, Ultramarine, Navy Blue, Cobalt Blue, Carbon Black, Carbon Fiber, Carbon Nanofiber, Carbon Nanotube ( Single-walled nanotubes, double-walled nanotubes, multi-walled nanotubes) and the like. The pigment is preferably a carbon material such as carbon black from the viewpoint of versatility.
The content of the pigment is preferably 1 to 75% by mass, more preferably 10 to 50% by mass, when the total mass of the non-aqueous dispersion is 100% by mass.

Examples of the non-aqueous solvent (organic solvent) serving as a dispersion medium for dispersing the pigment in the non-aqueous dispersion composition of the present invention include aromatic hydrocarbon solvents such as toluene and xylene, and hydrocarbon solvents such as cyclohexane. Ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate and n-propyl acetate, glycol ether solvents such as ethylene glycol monoethyl ether and ethylene glycol monoisopropyl ether, ethylene glycol monoethyl ether acetate and propylene glycol. Glycol ether ester solvents such as monomethyl ether acetate, terpene solvents such as tarpineol, dihydro tarpineol and dihydro tarpinyl acetate, alcohol solvents such as methanol, ethanol and isopropanol can be mentioned, and one selected from these non-aqueous solvents. Alternatively, two or more types can be used.
The content of the non-aqueous solvent is preferably 10 to 1000 parts by mass, more preferably 50 to 500 parts by mass, and even more preferably 100 to 300 parts by mass with respect to 100 parts by mass of the pigment.

The non-aqueous solvent has a solubility parameter (SP value) of 8.5 to 12.5 (cal / cm ³ ) 1 / from the viewpoint of improving the dispersibility of the pigment and compatibility with the polyoxyalkylene derivative component in the present invention. The value of 2 is preferable. The solubility parameter (SP value) of a non-aqueous solvent can be calculated by Hansen's formula, and the details can be found in "SP Value Basics / Applications and Calculation Methods" (Hideki Yamamoto, published by Information Organization, 2006). It is described and is required based on this description. Specific examples of non-aqueous solvents having a solubility parameter (SP value) in the above range are toluene, methyl ethyl ketone, ethyl acetate, n-propyl acetate, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, and propylene glycol monomethyl ether. Examples thereof include acetate, tarpineol, dihydroterpineol, dihydroterpinyl acetate, isopropanol and the like, and propylene glycol monomethyl ether acetate is more preferable. Further, even if the solubility parameter (SP value) is a non-aqueous solvent outside the range of 8.5 to 12.5 (cal / cm3) 1/2, the above range can be obtained by combining two or more kinds of non-aqueous solvents. The SP value can also be adjusted.

The non-aqueous dispersion composition of the present invention can be blended with various additives such as other surfactants, binders, plasticizers and antifoaming agents as long as the purpose is not impaired.

The non-aqueous dispersion composition of the present invention can be produced according to a known method for producing a non-aqueous dispersion composition. For example, a method of adding a dispersion to a non-aqueous solvent in which a non-aqueous dispersant is dissolved and then stirring and mixing at room temperature, or adding a non-aqueous solvent and dispersant to a pigment and then stirring at room temperature. Examples include a mixing method.
As a dispersion device for stirring, mixing, or dispersing, a known disperser can be used. For example, a roll mill, a ball mill, a bead mill, a sand mill, a homogenizer, a disper, a rotation / revolution type mixer and the like can be mentioned. Further, the dispersion treatment can be performed in the ultrasonic wave generation bath.

Hereinafter, the present invention will be described with reference to specific examples.
(Preparation of dispersant)
(Synthesis example 1)
110 g (0.2 mol) of the polyoxyalkylene derivative shown in Table 1, 36.4 g (0.21 mol) of N-phenylmaleimide, and 22.0 g of toluene as a solvent were added to a 0.3 liter flask equipped with a stirrer, a thermometer, and a nitrogen gas introduction tube. Under a nitrogen gas atmosphere, add 2.8 g (0.01 mol) of 2,2'-azobis (isobutyric acid) dimethyl as a polymerization initiator, the first step: 60 ± 5 ° C. for 1 hour, the second step: 75 ± 5 The reaction was carried out at ° C. for 4 hours and the third step: 85 ± 5 ° C. for 3 hours to obtain a copolymer. As a result of measuring the molecular weight of the obtained copolymer by GPC, the weight average molecular weight was 18,000.

(Synthesis example 2)
170 g (0.1 mol) of the polyoxyalkylene derivative shown in Table 1 and 19.9 g (0.11 mol) of N-phenylmaleimide were added to a 0.3 liter flask equipped with a stirrer, a thermometer, and a nitrogen gas introduction tube. Under a nitrogen gas atmosphere, 2.1 g (0.01 mol) of 2,2'-azobis (isobutyric acid) dimethyl as a polymerization initiator was added, and the first step: 60 ± 5 ° C. for 1 hour, the second step: 75 ± 5 The reaction was carried out at ° C. for 4 hours and the third step: 85 ± 5 ° C. for 3 hours to obtain a copolymer. As a result of measuring the molecular weight of the obtained copolymer by GPC, the weight average molecular weight was 33,000.

(Synthesis example 3)
In a 0.5 liter flask equipped with a stirrer, thermometer, and nitrogen gas introduction tube, 255 g (0.15 mol) of the polyoxyalkylene derivative shown in Table 1, 11.8 g (0.12 mol) of maleic anhydride, and 9.0 g (0.05 mol) of N-phenylmaleimide Was added. Under a nitrogen gas atmosphere, 3.1 g (0.01 mol) of 2,2'-azobis (isobutyric acid) dimethyl as a polymerization initiator was added, and the first step: 60 ± 5 ° C. for 1 hour, the second step: 75 ± 5 The reaction was carried out at ° C. for 4 hours and the third step: 85 ± 5 ° C. for 3 hours to obtain a copolymer. As a result of measuring the molecular weight of the obtained copolymer by GPC, the weight average molecular weight was 35,000.

(Synthesis example 4)
In a 0.5 liter flask equipped with a stirrer, thermometer, and nitrogen gas introduction tube, 255 g (0.15 mol) of the polyoxyalkylene derivative shown in Table 1, 11.8 g (0.12 mol) of maleic anhydride, and 9.0 g (0.05 mol) of N-phenylmaleimide Was added. Under a nitrogen gas atmosphere, 3.1 g (0.01 mol) of 2,2'-azobis (isobutyric acid) dimethyl as a polymerization initiator was added, and the first step: 60 ± 5 ° C. for 1 hour, the second step: 75 ± 5 The reaction was carried out at ° C. for 4 hours and the third step: 85 ± 5 ° C. for 3 hours to obtain a copolymer. As a result of measuring the molecular weight of the obtained copolymer by GPC, the weight average molecular weight was 35,000.

(Synthesis example 5)
In a 0.5 liter flask equipped with a stirrer, thermometer, and nitrogen gas introduction tube, 255 g (0.15 mol) of the polyoxyalkylene derivative shown in Table 1, 12.6 g (0.13 mol) of maleic anhydride, and 3.6 g (0.02 mol) of N-phenylmaleimide Was added. Under a nitrogen gas atmosphere, 3.1 g (0.01 mol) of 2,2'-azobis (isobutyric acid) dimethyl as a polymerization initiator was added, and the first step: 60 ± 5 ° C. for 1 hour, the second step: 75 ± 5 The reaction was carried out at ° C. for 4 hours and the third step: 85 ± 5 ° C. for 3 hours to obtain a copolymer. As a result of measuring the molecular weight of the obtained copolymer by GPC, the weight average molecular weight was 35,000.

(Synthesis example 6)
255 g (0.15 mol) of the polyoxyalkylene derivative shown in Table 1 and 16.8 g (0.17 mol) of maleic anhydride were added to a 0.5 liter flask equipped with a stirrer, a thermometer, and a nitrogen gas introduction tube. Under a nitrogen gas atmosphere, 3.1 g (0.01 mol) of 2,2'-azobis (isobutyric acid) dimethyl as a polymerization initiator was added, and the first step: 85 ± 5 ° C. for 1 hour, the second step: 125 ± 5 The reaction was carried out at ° C. for 8 hours to obtain a copolymer. As a result of measuring the molecular weight of the obtained copolymer by GPC, the weight average molecular weight was 20,000.

(Dispersion experiment)
A dispersion composition was obtained as follows using carbon black (product name: MA-220, manufactured by Mitsubishi Chemical Corporation) having an average particle size of 55 nm as a pigment. That is, 1.5 g of carbon black was weighed into a 50 mL screw tube, and 0.23 g of each dispersant of Synthesis Examples 1 to 6 shown in Table 2, 3.27 g of propylene glycol monomethyl ether acetate, and 5.0 g of zirconia beads (φ0.5 mm) (φ0.5 mm). Equivalent to the total amount of the composition) was added, and the mixture was mixed and pulverized at 2,000 rpm for 15 minutes using a hybrid mixer.

However, in Comparative Example 2, BYK-2155 (a block copolymer having a pigment-compatible basic group) manufactured by BYK Chemie, which is remarkably effective in dispersing carbon black, was used as the dispersant.

The shear viscosity of the obtained dispersion composition at a shear rate of 100 (1 / s) at 20 ° C. was measured with a leometer to evaluate the dispersibility. In addition, the thixotropy index (TI value) was calculated from the following formula.

TI value = shear viscosity at shear rate 10 (1 / s) / shear viscosity at shear rate 100 (1 / s)

The evaluation criteria for dispersibility and thixotropy are as follows.
(Dispersity evaluation criteria)

⊚: When the shear viscosity at 100 (1 / s) is 80 mPa or less, it is regarded as “very good dispersibility”.
◯: When the shear viscosity is 100 mPa or less, it is considered as “good dispersibility”.
Δ: When the shear viscosity is 100 mPa or more, it is considered as “low dispersibility”.

(Thixotropic evaluation criteria)

⊚: It has excellent thixotropy when the TI value is 5.0 or more.
◯: Has excellent thixotropy when the TI value is 3.0 or more.
Δ: Thixotropy is low when the TI value is 3.0 or less.

The dispersion compositions of Examples 1 to 5 to which the compounds of Synthesis Examples 1 to 5 according to the present invention were added showed good dispersibility with a shear viscosity of 100 mPa · s or less. In addition, the TI value was large, showing excellent thixotropy, and it was possible to impart dispersibility and thixotropy with a single agent. In particular, the dispersion composition of Example 4 exhibited better dispersibility and thixotropy.

In the case of Comparative Example 1 using the compound of Synthesis Example 6, the TI value was sufficiently large and excellent thixotropy was exhibited, but the shear viscosity was high and sufficient dispersibility could not be obtained.
In the case of Comparative Example 2 using BYK-2155, the shear viscosity was low and good dispersibility was shown, but the TI value was low and thixotropy was not obtained.

From the results of the above Examples and Comparative Examples, the dispersant of the present invention disperses pigments in a non-aqueous solvent dispersion without the need to optimize the combination of additives, and can simultaneously impart dispersibility and thixotropic properties with a single agent. It turns out that it is an agent.

Claims (2)

A non-aqueous pigment dispersant that disperses pigments in a non-aqueous solvent.
It consists of a copolymer of the following monomer (a) and the following monomer (b).the law of nature, The composition ratio ((a): (b)) of the monomer (a) to the monomer (b) is 40:60 to 90:10 in mol%, and the weight of the copolymer. Non-aqueous system characterized by an average molecular weight of 5,000 to 50,000PigmentDispersant.

Monomer (a)
Polyoxyalkylene derivative represented by the formula (1)

R¹O (AO)_nR² (1)

(In equation (1)
R¹Indicates a hydrocarbon group having 1 to 4 carbon atoms.
R²Indicates an unsaturated hydrocarbon group having 3 to 4 carbon atoms having one double bond.
AO indicates one or more oxyalkylene groups having 2 to 3 carbon atoms,
n is the average number of moles of oxyalkylene group added and represents a real number from 1 to 100. )

Monomer (b)

N-substituted maleimide represented by equation (2)

(In equation (2), R³Indicates a hydrocarbon group having 1 to 15 carbon atoms. ) The non-aqueous pigment dispersion contains a pigment, a non-aqueous solvent and the non-aqueous pigment dispersant according to claim 1, and the content of the non-aqueous solvent is 10 to 1000 parts by mass with respect to 100 parts by mass of the pigment . A non-aqueous dispersion composition characterized in that the content of the agent is 1 to 100 parts by mass.