JP5364321B2 - Method for producing pigment dispersion for color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a pigment dispersion for a color filter capable of obtaining a cured film excellent in contrast and a colored composition for the color filter. <P>SOLUTION: In the method for producing the pigment dispersion containing a pigment (A), a polymer for dispersing the pigment (B) and an organic solvent (c-1) expressed by general formula (1), the method of producing the pigment dispersion for the color filter and the colored composition for the color filter include: an organic solvent (C) expressed by the organic solvent (c-1) and general formula (2), and also causing an organic solvent (c-2) having a viscosity of 0.3 to 1.0 mPa s at 25&deg;C to be present when the pigment (A) and the polymer for dispersing the pigment (B) are dispersed wherein R<SP>1</SP>, R<SP>2</SP>, R<SP>4</SP>and R<SP>5</SP>are each independently a hydrogen atom or a 1-5C hydrocarbon group respectively, and R<SP>3</SP>is a hydrogen atom or a methyl group. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a pigment dispersion for a color filter, and a coloring composition for a color filter.

Liquid crystal display devices (LCDs) are actively developed because they have the advantage of being small, light and large. A color filter is used for color development of the liquid crystal display device, and a pigment dispersion method is widely used as a method for producing the color filter.
In the pigment dispersion method, a color resist solution in which a pigment dispersion and a photosensitive composition are mixed is applied on a transparent substrate, and then a colored pattern is formed on the transparent substrate by exposure, curing, development, and heat curing. The pigment dispersion used in this pigment dispersion method contains a pigment, a dispersant, a solvent, and, if necessary, a resin.

By the way, it is known to use a plurality of solvents in a pigment dispersion used in a color filter. For example, in Patent Document 1, the first solvent having a viscosity of 1.5 mPa · s or less and 1.5 mPa · s is exceeded with the object of making the film thickness uniform and making the image smooth and transparent. A colored image forming photosensitive solution using a mixture with a second solvent having a viscosity is disclosed.
Further, Patent Document 2 discloses a die coat used for a color filter or the like using two kinds of solvent mixtures having different boiling points and different absolute values of SP values from the curable resin composition, with the object of reducing the generation of foreign matter. A curable resin composition is disclosed.
Patent Document 3 discloses an inkjet ink for a color filter containing a first solvent having a boiling point of 180 to 260 ° C. and a second solvent having a boiling point of 130 ° C. or more and less than 180 ° C. for the purpose of reducing surface unevenness. .

Japanese Patent Laid-Open No. 11-24245 JP 2004-246340 A JP 2007-328062 A

In an LCD using a color filter using a color filter pigment dispersion, there is a problem that the contrast is insufficient. This is because it is difficult to miniaturize the pigment to a satisfactory extent, and if a pigment dispersion that is insufficiently miniaturized is used, it causes scattering and absorption of transmitted light in the LCD. It is considered that this does not improve the contrast.
This invention makes it a subject to provide the manufacturing method of the pigment dispersion for color filters which can obtain the cured film excellent in contrast, and the coloring composition for color filters.

The present inventors have found that in the production of a pigment dispersion for a color filter, the above-mentioned problems can be solved by using two specific organic solvents when dispersing the dispersion raw material.
That is, the present invention provides the following [1] and [2].
[1] A method for producing a pigment dispersion comprising a pigment (A), a pigment dispersing polymer (B), and an organic solvent (c-1) represented by the following general formula (1), wherein the pigment (A ) And the pigment dispersing polymer (B), the organic solvent (C-1) and the following general formula (2) are represented as the organic solvent (C), and the viscosity at 25 ° C. is 0.3 to The manufacturing method of the pigment dispersion for color filters which makes the organic solvent (c-2) which is 1.0 mPa * s exist.

（式中、Ｒ¹及びＲ²はそれぞれ独立に、水素原子又は炭素数１〜５の炭化水素基を示し、Ｒ³は水素原子又はメチル基を示し、ｎは平均付加モル数を示し、１〜４である。）

(Wherein R ¹ and R ² each independently represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, R ³ represents a hydrogen atom or a methyl group, n represents an average number of added moles, ~ 4.)

（式中、Ｒ⁴及びＲ⁵はそれぞれ独立に、水素原子又は炭素数１〜５の炭化水素基を示す。）

(In the formula, R ⁴ and R ⁵ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.)

[2] A color filter coloring composition containing the color filter pigment dispersion obtained by the production method of [1].

  According to the present invention, there are provided a method for producing a pigment dispersion for a color filter capable of obtaining a cured film excellent in contrast, and a color composition for a color filter containing the dispersion obtained by the production method. Can do.

In the method for producing a pigment dispersion for a color filter of the present invention, the pigment (A), the pigment dispersion polymer (B), and the organic compounds represented by the general formulas (1) and (2) are used as raw material components at the time of dispersion. Solvents (c-1) and (c-2) are used.
First, each of these components will be described.

[Pigment (A)]
The pigment (A) used in the present invention may be either an inorganic pigment or an organic pigment. If necessary, these and extender pigments can be used in combination.
Examples of the inorganic pigment include carbon black, metal oxide, metal sulfide, and metal chloride.
Examples of organic pigments include azo pigments, phthalocyanine pigments, condensed polycyclic pigments, and lake pigments. As the azo pigment, C.I. I. Insoluble azo pigments such as CI Pigment Red 3; I. Soluble red azo pigments such as CI Pigment Red 48: 1; I. And condensed azo pigments such as CI Pigment Red 144. Examples of the phthalocyanine pigment include C.I. I. And copper phthalocyanine pigments such as CI Pigment Blue 15: 6.
Examples of the condensed polycyclic pigment include C.I. I. Anthraquinone pigments such as CI Pigment Red 177; I. Perylene pigments such as CI Pigment Red 123; I. Perinone pigments such as C.I. Pigment Orange 43; I. Quinacridone pigments such as C.I. Pigment Red 122; I. Dioxazine pigments such as CI Pigment Violet 23, C.I. I. Pigment Yellow 109 and other isoindolinone pigments, C.I. I. Pigment Orange 66 and other isoindoline pigments, C.I. I. Quinophthalone pigments such as CI Pigment Yellow 138; I. Indigo pigments such as CI Pigment Red 88; I. Metal complex pigments such as C.I. Pigment Green 8; I. Pigment red 254, C.I. I. Pigment red 255, C.I. I. And diketopyrrolopyrrole pigments such as CI Pigment Orange 71.
Among these, a diketopyrrolopyrrole pigment represented by the following general formula (1) is preferable from the viewpoint of more effectively expressing the effects of the present invention.

In formula (1), X ¹ and X ² each independently represent a hydrogen atom or a halogen atom, and Y ¹ and Y ² each independently represent a hydrogen atom or a —SO ₃ H group. The halogen atom is preferably a fluorine atom or a chlorine atom.
For the pigment (A), it is desirable to use an atomized product having an average primary particle size of preferably 100 nm or less, more preferably 20 to 60 nm, from the viewpoint of improving the brightness Y value. The average primary particle diameter of the pigment can be obtained by directly measuring the size of the primary particles from an electron micrograph. Specifically, the short axis diameter and the long axis diameter of each primary particle are measured, and the average value thereof is defined as the particle diameter of the particle. For 100 or more particles, the volume of each particle is expressed as one side of the particle diameter. The volume average particle diameter is obtained by approximating to the cube as described above, and this is used as the average primary particle diameter.
Preferable examples of commercially available diketopyrrolopyrrole pigments include Ciba Specialty Chemicals, Inc., C.I. I. Pigment Red 254, trade names "Irgaphor Red B-CF", "Igaphor Red BK-CF", "Irgaphor Red BT-CF", "Irgazin DPP Red BO", "Irgazin DPP Red BL", "Cromophtal DPP Red BP" , “Cromophtal DPP Red BOC” and the like.
The above-mentioned pigment (A), particularly diketopyrrolopyrrole pigment, can be used alone or in combination of two or more.

[Pigment dispersing polymer (B)]
The pigment dispersing polymer is a polymer used to disperse the pigment.
The pigment-dispersing polymer (B) used in the present invention may be any pigment (A), particularly a diketopyrrolopyrrole pigment that can be dispersed in an organic solvent (C) in a state of being stably finely divided. A known pigment dispersion polymer can be used. This pigment dispersing polymer (B) is considered to function as a binder when forming a color filter.
Examples of the pigment dispersing polymer (B) include an amide skeleton in the main chain described in JP-A-3-277673, JP-A-10-339949, JP-T-2003-517063, etc. Graft polymer whose chain is composed of a macromonomer based on methacrylic acid ester; polyester oligomer having an aliphatic hydroxycarboxylic acid residue described in JP-B-7-96654, JP-A-7-207178, etc .; organosiloxane polymer (Shin-Etsu) Manufactured by Chemical Industry Co., Ltd., trade name: KP341, etc.); (meth) acrylic acid-based (co) polymer (manufactured by Kyoei Yushi Chemical Co., Ltd., trade name: Polyflow No. 75, 90, 95, etc.); polyoxyethylene Lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether Nonionic surfactants such as polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate, and sorbitan fatty acid ester; Cationic interfaces such as those manufactured by Yusho Co., Ltd., trade name: W001 Activating agent: Yusho Co., Ltd., trade names: W004, W005, W017 and other anionic surfactants; AstraZeneca Co., Ltd., trade names: Solsperse 3000, 5000, 9000, 12000, 13240, 13940, 17000, 20000 , 24000, 26000, 28000, etc., trade names of Ajinomoto Fine Techno Co., Ltd .: Ajisper PB-821, PB-822, trade names of Sanyo Kasei Co., Ltd .: Isonet S 20, and the like.

In these, the graft polymer obtained by coupling-reacting the following (b1) component and (b2) component from a viewpoint of the fine stabilization of a pigment is preferable.
Component (b1): a copolymer (b2) component containing a structural unit derived from a vinyl monomer (b1a) containing a reactive functional group and a vinyl monomer (b1b) containing a nitrogen atom The specific copolymer which is a poly (meth) acrylate alkyl and / or polystyrene (b1) component having a functional group capable of reacting with the reactive functional group of the component (b1) is a component of the pigment dispersing polymer (B). The specific poly (meth) acrylate and / or polystyrene that constitutes the main chain and is the component (b2) constitutes a side chain that is grafted to the main chain.

[(B1) component]
The component (b1) is a copolymer including a structural unit derived from a vinyl monomer (b1a) containing a reactive functional group and a structural unit derived from a vinyl monomer (b1b) containing a nitrogen atom. It can be obtained by copolymerizing a monomer mixture containing b1a) and (b1b).
When the component (b1) has the above-described configuration, polymer modification or the like can be performed using the remaining reactive functional group while maintaining the pigment adsorptivity of the pigment-dispersing polymer (B).

[Reactive Functional Group-Containing Vinyl Monomer (b1a)]
Examples of the vinyl monomer containing a reactive functional group include vinyl monomers containing an epoxy group, an isocyanate group, a carboxy group, a phosphoric acid group, a sulfonic acid group, and an amino group.
Examples of vinyl monomers containing an epoxy group include (meth) acrylic acid esters such as glycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, 3,4-epoxycyclohexylmethyl (meth) acrylate, N -(Meth) acrylamides such as glycidyl (meth) acrylamide, allyl ethers such as allyl glycidyl ether, 1,2-epoxy-5-hexene and the like.
As the vinyl monomer containing an isocyanate group, 2-methacryloyloxyethyl isocyanate (product name: Karenz MOI), 2-[(3,5-dimethylpyrazolyl) carboxyamino] ethyl, which is an isocyanate monomer manufactured by Showa Denko KK Methacrylate (product name: Karenz MOI-BP), 2-([1'-methylpropylideneamino] carboxyamino) ethyl methacrylate (Product name: Karenz MOI-BM), 2-acryloyloxyethyl isocyanate (Product name: Karenz) AOI) and the like.

Examples of the vinyl monomer containing a carboxy group include (meth) acrylic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl phthalic acid, and the like.
Examples of the vinyl monomer containing a phosphoric acid group include mono (2-methacryloyloxyethyl) acid phosphate and mono (2-acryloyloxyethyl) acid phosphate.
Examples of the vinyl monomer containing a sulfonic acid group include acrylamide 2-methylpropanesulfonic acid.
Examples of the vinyl monomer containing an amino group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 2-vinylpyridine, 4-vinylpyridine and the like.
In these, the vinyl monomer containing an epoxy group is preferable from the surface of reactivity and a polymerization rate, (meth) acrylic acid ester containing a glycidyl group is preferable, and (meth) acrylic acid glycidyl is more preferable.
In the present specification, “(meth) acrylic acid” means acrylic acid, methacrylic acid, or both.

[Vinyl monomer containing nitrogen atom (b1b)]
As the vinyl monomer containing a nitrogen atom, a vinyl monomer having an amide bond is preferable, and more specifically, (meth) acrylamides, vinylpyrrolidones, vinylpyridines, nitrogen-containing styrenic monomers, nitrogen-containing (meth) Examples include acrylic acid esters.
(Meth) acrylamides include (meth) acrylamide, N, N-dialkyl (meth) acrylamide (the alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms), and N-alkyl (meta). ) Acrylamide (the alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms), N, N-dialkyl (the alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms) Aminoalkyl (the alkyl group preferably has 1 to 6 carbon atoms) (meth) acrylamide, (meth) acrylamide 2-methylpropylsulfonic acid, morpholino (meth) acrylamide, piperidino (meth) acrylamide, N-methyl-2-pyrrolidyl (Meth) acrylamide, N, N-methylphenyl (meth) acrylamide and the like can be mentioned.
Examples of vinyl pyrrolidones include N-vinyl-2-pyrrolidone.

Examples of vinylpyridines include 2-vinylpyridine and 4-vinylpyridine, and examples of nitrogen-containing styrene monomers include p-styrenesulfonamide, p-aminostyrene, and aminomethylstyrene.
As the nitrogen-containing (meth) acrylic acid ester, N, N-dialkyl (the carbon number of the alkyl group is preferably 1 to 8, more preferably 1 to 4) aminoalkyl (the carbon number of the alkyl group is preferably 1 to 6). ) (Meth) acrylate, 1- (N, N-dialkylamino) -1,1-dimethylmethyl (meth) acrylate (the carbon number of the alkyl group is preferably 1-8, more preferably 1-4), Morpholinoethyl (meth) acrylate, piperidinoethyl (meth) acrylate, 1-pyrrolidinoethyl (meth) acrylate, N, N-dimethyl-2-pyrrolidylaminoethyl (meth) acrylate, N, N-methylphenylaminoethyl (meth) ) Acrylate and the like.
Among these, (meth) acrylamides and vinylpyrrolidones are preferable and N-vinylpyrrolidone is more preferable from the viewpoint of adsorptivity to the pigment.

[Other monomer (b1c)]
The component (b1) is a copolymer containing a structural unit derived from the vinyl monomer (b1a) and a structural unit derived from the vinyl monomer (b1b), but within the range not impairing the effects of the present invention, Other polymerizable monomers (b1c) can be copolymerized.
Other monomers (b1c) include methyl (meth) acrylate, ethyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, (meth) acrylic acid 2 -(Meth) acrylic esters such as hydroxyethyl, glycerol mono (meth) acrylate, perfluorooctylethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, styrenes such as styrene, vinyl esters such as vinyl acetate And vinyl ethers such as butyl vinyl ether. Among these, monomers having an alcoholic hydroxyl group such as 2-hydroxyethyl (meth) acrylate are preferable.
Each of the monomers (b1a), (b1b) and (b1c) can be used alone or in combination of two or more.
The content of the structural unit derived from the monomers (b1a), (b1b), and (b1c) in the component (b1) is not particularly limited, but the structural unit derived from (b1a) is 5 to 95% by weight, (b1b ) -Derived structural units are preferably 5 to 95% by weight, and (b1c) -derived structural units are preferably 0 to 80% by weight.

[Production of component (b1)]
(B1) There is no restriction | limiting in particular in the manufacturing method of a component, Although a bulk polymerization method, a solution polymerization method, a suspension polymerization method, etc. can be employ | adopted, a solution polymerization method is preferable. The solvent used in the solution polymerization method is not particularly limited, and examples thereof include alcohols such as ethanol, ketones, esters, hydrocarbons, ethers, aromatic compounds, and halogenated hydrocarbons.
Examples of the polymerization initiator include azo initiators such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile), peroxide initiators, and persulfuric acid initiators. An initiator etc. are mentioned. Moreover, chain transfer agents, such as mercaptans, such as dodecyl mercaptan, mercaptoethanol, mercaptopropionic acid, etc. can also be used as needed.
The reaction temperature can be appropriately selected depending on the polymerization initiator used, the type of solvent, and the like, but is usually preferably in the range of 50 to 100 ° C.

The number average molecular weight of the component (b1) is preferably 500 to 50,000, more preferably 1000 to 30 from the viewpoint of suppressing the storage stability as the dispersion of the composition of the present invention and the decrease in the dispersion rate of the pigment. 2,000, more preferably 2000 to 20,000. Moreover, the weight average molecular weight of (b1) component is from the same viewpoint, Preferably it is 1500-150,000, More preferably, it is 3000-90,000, More preferably, it is 6000-60,000.
The epoxy value of the component (b1) is preferably 19 to 375 mgKOH / g, more preferably 30 to 350 mgKOH / g, and particularly preferably 40 to 300 mgKOH / g from the viewpoint of reactivity with the component (b2). The number average molecular weight and epoxy value of the component (b1) can be obtained by adjusting the copolymerization conditions such as the monomers (b1a) and (b1b). The number average molecular weight and epoxy value can be measured by the methods described in the examples.

[(B2) component]
The component (b2) is an alkyl poly (meth) acrylate and / or polystyrene having a functional group capable of reacting with the reactive functional group of the component (b1) at one end.
Examples of the functional group capable of reacting with the reactive functional group of the component (b1) include a carboxy group, a hydroxyl group, an amino group, an epoxy group, an isocyanate group, and the like, and considering the type of the reactive functional group of the component (b1). And can be selected as appropriate.
When the reactive functional group of the component (b1) is an epoxy group, the component (b2) is a polymer having a carboxy group at one end (a polymer at one end carboxylic acid type) or a polymer having an amino group at one end. It is preferably a polymer (one-terminal amino group type polymer).
When the reactive functional group of the component (b1) is an isocyanate group, the component (b2) is a polymer having a hydroxyl group at one end (a polymer at one end hydroxyl group type) or a polymer having an amino group at one end. It is preferably a polymer (one-terminal amino group type polymer).

As one-end carboxylic acid type polymer, poly (meth) methyl acrylate, poly (meth) ethyl acrylate, poly (meth) acrylate butyl, or poly (meth) acrylate stearyl having a carboxy group at one end One terminal carboxylic acid type poly (meth) acrylic acid alkyl or one terminal carboxylic acid type polystyrene.
As the one-terminal amino group type polymer, poly (meth) methyl acrylate, poly (meth) ethyl acrylate, poly (meth) acrylate butyl, or poly (meth) acrylate stearyl having an amino group at one end One terminal amino group type poly (meth) acrylic acid such as one terminal amino group type polystyrene or the like.
One terminal hydroxyl group-type polymer includes poly (meth) acrylate methyl, poly (meth) ethyl acrylate, poly (meth) acrylate butyl, or poly (meth) acrylate stearyl having a hydroxyl group at one end. One-terminal hydroxyl group-type poly (meth) acrylates such as one-terminal hydroxyl group-type polystyrene and the like.
Among these, a polymer having high solubility in the solvent to be used can be selected and used. For example, when propylene glycol monomethyl ether acetate is used as a solvent, it is preferable to use one-end carboxylic acid type polymethyl methacrylate, one-end carboxylic acid type polystyrene, or the like.

  A small amount of another monomer having a functional group can be copolymerized with the component (b2) as necessary. As these monomers, the monomer constituting the component (b1), a monomer (b1c) having an alcoholic hydroxyl group such as 2-hydroxyethyl methacrylate, a monomer (b1a) having a carboxy group such as methacrylic acid, methacrylic acid Examples thereof include a monomer (b1a) having an epoxy group such as glycidyl. The amount of copolymerization is not particularly limited as long as it does not hinder the coupling reaction between the component (b1) and the component (b2), but is preferably less than 10% by weight.

[Production of component (b2)]
There is no restriction | limiting in particular in the manufacturing method of (b2) component, Although a bulk polymerization method, a solution polymerization method, a suspension polymerization method, etc. can be employ | adopted, a solution polymerization method is especially preferable. The solvent, polymerization initiator, chain transfer agent, and reaction temperature used in the solution polymerization method are the same as those described in the production of the component (b1) and conditions. In order to introduce a carboxylic acid at one end, a polymerization initiator containing a carboxylic acid such as 4,4′-azobis (4-cyanobutyric acid) or a chain transfer agent containing a carboxylic acid such as mercaptopropionic acid is used. It is preferable to use a chain transfer agent such as aminoethanethiol for introducing an amino group at one end, and a chain transfer agent such as mercaptoethanol for introducing a hydroxyl group at one end.
The number average molecular weight of the component (b2) is preferably 500 to 20,000, more preferably 700 to 10,000, and particularly preferably from the viewpoint of storage stability as a dispersion of the composition of the present invention and suppression of thickening. Is 700-6000.
Further, the molar ratio of the functional group of the component (b2) to the reactive functional group of the component (b1) [the functional group of the component (b2) / the reactive functional group of the component (b1))] is the unreacted (c2). From the viewpoint of suppression, 0.05 to 1.0 is preferable, 0.1 to 0.9 is more preferable, and 0.2 to 0.8 is particularly preferable.

[Production of pigment dispersion polymer (B)]
The pigment dispersing polymer (B) is produced by a coupling reaction between the reactive functional group of the component (b1) and the functional group of the component (b2) that can react with the reactive functional group.
A catalyst may be used in the coupling reaction. In particular, in the case of a reaction between an epoxy group and a carboxylic acid or a reaction between an isocyanate group and a hydroxyl group, it is preferable to add a catalyst. Examples of the catalyst for the reaction between the epoxy group and the carboxylic acid include quaternary ammonium salts, tertiary amines, alkali metal hydroxides, inorganic acids, sulfonic acids, carboxylic acids, solid acids, solid bases and the like.
Examples of the quaternary ammonium salt include halides such as tetraethylammonium bromide, tetrabutylammonium bromide, tetrabutylammonium iodide, tetramethylammonium chloride, trimethylbenzylammonium chloride, triethylbenzylammonium chloride. Include triethylamine, dimethylbutylamine, diisopropylethylamine, 2,2,6,6-tetramethylpiperidine and the like.
Among the above catalysts, quaternary ammonium salts and tertiary amines are preferable, quaternary ammonium halides are more preferable, and tetrabutylammonium bromide is particularly preferable. Although there is no restriction | limiting in particular about the addition amount of a catalyst, 0.5-200 mol% is preferable with respect to carboxylic acid.
Examples of the catalyst for the reaction of an isocyanate group and a hydroxyl group include amines such as pyridine and organic metals such as dibutyltin dilaurate. Although there is no restriction | limiting in particular about the addition amount of a catalyst, 0.05-200 mol% is preferable with respect to an isocyanate group.

The solvent is not particularly limited as long as it can dissolve the component (b1) and the component (b2). A solvent can be used individually or in combination of 2 or more types.
Although there is no restriction | limiting in particular in the density | concentration of a reaction system, The total amount of the (b1) component and (b2) component in whole quantity is from a viewpoint which suppresses a viscosity raise and ensures favorable handling property, and shortens reaction time. , Preferably 5 to 70% by weight, more preferably 10 to 50% by weight. The reaction temperature is not particularly limited, but is preferably 60 ° C. or higher from the viewpoint of the reaction rate.
The progress of the coupling reaction can be confirmed by quantifying each reactive functional group. For example, when using the (b1) component having an epoxy group and the (b2) component having a carboxy group, the acid value and epoxy group in the reaction system are measured, and the (b2) component having an amino group is used. In this case, the progress of the coupling reaction can be confirmed by measuring the amine value.

In the polymer (B) for pigment dispersion obtained by the above method, the content of the constituent component derived from the component (b1a) in all the constituent units is the viewpoint of the adsorptivity to the pigment, the suppression of increase in viscosity, and the dispersed particle size. From the viewpoint of optimization, the content is preferably 0 to 65% by weight, more preferably 0 to 50% by weight, and still more preferably 0 to 45% by weight.
The content of the component derived from the component (b1b) in all the structural units of the pigment-dispersing polymer (B) is preferably from the viewpoint of adsorptivity to the pigment, suppression of increase in viscosity, and optimization of the dispersed particle size. Is 1 to 30% by weight, more preferably 2 to 25% by weight, still more preferably 5 to 20% by weight.
The content of the structural unit derived from the component (b2) in all the structural units of the pigment-dispersing polymer (B) is preferably 30 to 95% by weight from the viewpoint of adsorptivity to the pigment and the suppression of increase in viscosity. More preferably, it is 40 to 90 weight%, More preferably, it is 50 to 80 weight%.
From the same viewpoint, the weight average molecular weight of the pigment dispersing polymer (B) is preferably 1000 to 1,000,000, more preferably 2000 to 800,000, and still more preferably 5000 to 700,000.

[Organic solvent (c-1)]
In the present invention, an organic solvent (c-1) represented by the following general formula (1) is used.

In the formula, each of R ¹ and R ² independently represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, R ³ represents a hydrogen atom or a methyl group, and n is an average added mole number of 1 to 4. is there.
As the organic solvent (c-1), a high boiling point organic solvent having a boiling point at 1 atm of 100 ° C. or more, preferably 110 ° C. to 300 ° C., more preferably 120 to 280 ° C., and further preferably 130 to 260 ° C. preferable.
From the viewpoint of dispersibility of the pigment (A) and the viewpoint of making the pigment dispersion oily, the SP value (solubility parameter) of the organic solvent (c-1) is 8.0 to 9.6 (cal / cm). ³⁾ is preferably ^1/2 is, more preferably ^{8.2~9.3 (cal / cm 3) 1/2} , 8.4~9.0 (cal / cm 3) 1 / ² is more preferable. The SP value of the organic solvent (c-1) can be calculated by the Fedors method [Robert F. Fedors, Polymer Engineering and Science, 14, 147-154 (1974)]. The same applies to the organic solvent (c-2) described later.
The organic solvent (c-1) has a viscosity at 25 ° C. of 0.8 to 5.0 mPa · s and 0.9 to 4.0 mPa from the viewpoint of improving the contrast of the cured film using the pigment dispersion. · It is preferably s, and more preferably 1.0 to 3.5 mPa · s.

As the organic solvent (c-1), alkylene glycol monoalkyl ether acetate, polyalkylene glycol monoalkyl ether acetate, and alkylene glycol monoalkyl ether propionate are preferable, and specific examples thereof include ethylene glycol monomethyl ether acetate and ethylene glycol. Monoethyl ether acetate, ethylene glycol monomethyl ether propionate, ethylene glycol monoethyl ether propionate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate , Diethylene glycol monomethyl ether Acetate, diethylene glycol monobutyl ether acetate and the like.
Among these, from the viewpoint of the solubility or dispersibility of the pigment dispersing polymer (B) and the dispersibility of the pigment (A), particularly the diketopyrrolopyrrole pigment, propylene glycol monomethyl ether acetate (PGMEA, boiling point: 146 Viscosity at 25 ° C .: 1.1 mPa · s, SP value: 8.73), diethylene glycol monobutyl ether acetate (BCA, boiling point: 247 ° C., viscosity at 25 ° C .: 3.1 mPa · s, SP value: 8) .94) is preferred.

[Organic solvent (c-2)]
In the present invention, an organic solvent (c-2) represented by the following general formula (2) is used in order to reduce the viscosity at the time of dispersion and promote the refinement of the pigment.

In the formula, R ⁴ and R ⁵ are each independently a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, but when R ⁴ and R ⁵ are hydrocarbon groups, the viscosity during dispersion is further reduced. From the viewpoint of making it, it is preferable that the total number of carbon atoms of both is 1-6.
The organic solvent (c-2) has a viscosity at 25 ° C. of 0.3 to 1.0 mPa · s from the viewpoint of promoting the miniaturization of the pigment and improving the contrast of the cured film using the pigment dispersion. 0.35 to 0.9 mPa · s, and more preferably 0.4 to 0.8 mPa · s. Moreover, it is preferable that the boiling point at 1 atm is 30 to 110 ° C., more preferably 40 to 105 ° C., more preferably 50 to 100 ° C. More preferably.
From the viewpoint of dispersibility of the pigment (A) and the viewpoint of making the pigment dispersion oily, the SP value (solubility parameter) of the organic solvent (c-2) is 8.0 to 9.2 (cal / cm). ³⁾ is preferably ^1/2 is, more preferably ^{8.2~9.1 (cal / cm 3) 1/2} , 8.4~8.9 (cal / cm 3) 1 / ² is more preferable.

The organic solvent (c-2) represented by the general formula (2) is a carboxylic acid alkyl ester, and specific examples thereof include, for example, methyl formate, ethyl formate, propyl formate, butyl formate, isobutyl formate, pentyl formate, and the like. Formate ester, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, secondary butyl acetate, etc. acetate, methyl propionate, ethyl propionate, propionate such as propyl propionate, methyl butyrate, Examples include butyric acid esters such as ethyl butyrate.
Among these, from the viewpoint of solubility or dispersibility of the pigment-dispersing polymer (B) and dispersibility of the pigment (A), particularly the diketopyrrolopyrrole pigment, acetate is preferable, and isopropyl acetate (25 Viscosity at 0 ° C .: 0.57 mPa · s, SP value: 8.50, boiling point: 89 ° C., methyl acetate (viscosity at 25 ° C .: 0.39 mPa · s, SP value: 8.78, boiling point: 58 ° C. ), Methyl butyrate (viscosity at 25 ° C .: 0.53 mPa · s, SP value: 8.72, boiling point: 102 ° C.).
Said organic solvent (c-1) and (c-2) can be used individually or in combination of 2 types or more, respectively.

(Production of pigment dispersion)
The method for producing a pigment dispersion for a color filter of the present invention comprises a pigment dispersion containing a pigment (A), a pigment dispersion polymer (B), and an organic solvent (c-1) represented by the following general formula (1). A method for producing a body, wherein when the pigment (A) and the pigment dispersing polymer (B) are dispersed, the organic solvent (C) is represented by the organic solvent (c-1) and the following general formula (2): And the organic solvent (c-2) whose viscosity in 25 degreeC is 0.3-1.0 mPa * s is made to exist.
There is no particular limitation on the dispersion method, and the desired pigment dispersion may be obtained by a single dispersion. Preferably, however, the pigment (A) is a powder having a large particle size, the pigment dispersion polymer (B), and the organic To disperse the solvent (C) ((c-1) and (c-2)) and mix them uniformly, perform preliminary dispersion, and then perform this dispersion treatment to refine the pigment. Is preferred.

[Preliminary dispersion process]
In the preliminary dispersion of the pigment (A), the pigment dispersion polymer (B) and the organic solvent (C), all the components may be mixed and dispersed at one time. However, the pigment dispersion polymer (B) and the organic solvent (C ) In advance to prepare a premix, and the premixture obtained is mixed with the pigment (A) and dispersed to obtain a final mixture.
The weight ratio [(A) / (B)] of the pigment (A) and the pigment dispersing polymer (B) at the time of preliminary dispersion is from the viewpoint of adhering a required amount of the pigment dispersing polymer (B) to the pigment (A). The weight ratio [(A) / (B)] is preferably 100/30 to 100/70, and more preferably 100/30 to 100/70.
The dispersion time for the preliminary dispersion is not particularly limited, but is preferably 0.1 to 10 hours, more preferably 0.5 to 4 hours, and still more preferably 1 to 3 hours.

There is no particular limitation on the mixing and dispersing machine used for the preliminary dispersion, and various known dispersing machines can be used. For example, commonly used mixing and stirring devices equipped with anchor blades, etc., specific examples include Ultra Disper, Desperm (Asada Tekko Co., Ltd., trade name), Milder (Ebara Corporation, Taiheiyo Kiko Co., Ltd., trade name) ), TK homomixer, TK pipeline mixer, TK homo jetter, TK homomic line flow, high-speed agitating and mixing devices such as filmix (Primix Co., Ltd., trade name), and kneaders such as roll mills, kneaders and extruders. High pressure homogenizers represented by high pressure homogenizers (Izumi Food Machinery Co., Ltd., trade name), microfluidizers (Microfluidics, trade name), Nanomizer (Yoshida Kikai Kogyo Co., Ltd., trade name), Optimizer, Starburst (Suginomashi) Co., Ltd., a high-pressure dispersing machine such as a high-pressure homogenizer of the chamber type of trade name), a paint shaker, a bead mill, Dyno (Shinmaru Enterprises Co., Ltd., and a media type dispersing machine such as a trade name), and the like. A plurality of these devices can be combined.
Among these, a paint shaker, a bead mill, and a high-pressure disperser are preferable from the viewpoint of miniaturization of the pigment (A), and a high-pressure disperser is more preferable from the viewpoint of improving contrast. In the high-pressure disperser, since the entire liquid passes through the flow path, the bias is less likely to occur compared to other dispersion methods. Therefore, it is considered that a homogeneous preliminary dispersion of pigment can be obtained. By using a homogeneous preliminary dispersion, it is possible to suppress the generation of coarse particles and the like in the main dispersion and improve the contrast.

[This dispersion process]
In order to further refine the mixture obtained by the above preliminary dispersion, it is preferable to perform this dispersion. This dispersion is preferably performed using a media-type disperser from the viewpoint of making the pigment (A) finer, and is preferably used in combination with the above-described high-pressure disperser from the viewpoint of improving contrast.
As the material of the medium used for this dispersion, ceramics such as zirconia and titania, polymer materials such as polyethylene and nylon, metals and the like are preferable, and zirconia is preferable from the viewpoint of wear. The particle size of the media is preferably 0.003 to 0.1 mm. From the viewpoint of making the pigment finer, 0.07 mm or less is more preferable, 0.05 mm or less is more preferable, and from the viewpoint of separating the media from the pigment, 0.005 mm or more is more preferable, and 0.01 mm or more is further preferable.
As the media type disperser used for the present dispersion, a paint shaker, a bead mill, etc. are preferable. Product name).

From the viewpoint of storage stability of the resulting dispersion, the temperature during dispersion is preferably maintained at 10 to 35 ° C, more preferably 15 to 30 ° C, and still more preferably 18 to 27 ° C.
Since heat is generated during dispersion, it is preferable to cool the disperser appropriately in order to maintain the temperature at 10 to 33 ° C. If the disperser is a paint shaker, it is preferable to cool using a spot cooler that blows cool air to the container containing the disperser. If the disperser is a bead mill, kneader, or high-pressure disperser, cool by flowing a coolant through the jacket. It is preferable.
The dispersion time of this dispersion is preferably 3 to 200 hours and more preferably 5 to 50 hours from the viewpoint of sufficiently miniaturizing the pigment (A).

The pigment dispersion polymer (B) may be added during the dispersion step. If the pigment dispersing polymer (B) is added, the dispersibility of the pigment (A) is improved, the viscosity is slightly lowered, and the stability of the pigment dispersion is also improved.
The weight ratio [(A) / (B)] of the pigment (A) and the pigment dispersing polymer (B) at the end of the dispersion is preferably 100/30 to 100/150 from the viewpoint of heat resistance and storage stability. 100 / 30-100 / 150 are more preferable.
The viscosity of the pigment dispersion is adjusted to 10 to 120 mPa · s (20 ° C.) by adjusting the mixing ratio of the power of the disperser and the pigment (A), the pigment dispersing polymer (B) and the organic solvent (C). It is preferable to adjust to 10 to 100 mPa · s (20 ° C.), more preferably 10 to 80 mPa · s (20 ° C.).

[Step of removing organic solvent (c-2)]
In the method for producing a pigment dispersion of the present invention, it is preferable that the organic solvent (c-2) is substantially removed after completion of dispersion from the viewpoint of improving the storage stability of the pigment dispersion.
Examples of the method for removing the organic solvent (c-2) include a method for efficiently removing the organic solvent (c-2) by atmospheric distillation, vacuum distillation, heat distillation, and a combination thereof.
Since the organic solvent (c-2) having a lower boiling point than that of the organic solvent (c-1) is preferably used, the organic solvent (c-2) can be efficiently removed by the above method, but does not impair the effects of the present invention. The organic solvent (c-1) may be removed in a small amount.
From the viewpoint of improving the storage stability of the pigment dispersion, the residual amount of the organic solvent (c-2) is preferably 10% by weight or less in the pigment dispersion, more preferably 5% by weight or less, More preferably, the content is 1% by weight or less.
There is no restriction | limiting in particular in the apparatus which removes an organic solvent (c-2), Rotary evaporator (The Tokyo Rika Co., Ltd. make, brand name EYELA A-1000S type), Solvent recovery distillation apparatus (Toshin Seiki Co., Ltd. PPA-4010FS type) Etc. can be preferably used.

[Other processes]
In the method for producing a pigment dispersion of the present invention, removal of unadsorbed polymer, redispersion using an organic solvent, and other steps can be performed.
As a method for removing the unadsorbed polymer, for example, a method of removing the polymer unadsorbed on the pigment (A) from the pigment dispersion by subjecting the pigment dispersion obtained in the dispersion step to membrane separation treatment or centrifugal separation treatment. Is mentioned.
Since removal of the unadsorbed polymer may cause aggregation of the pigment, it is preferable to perform redispersion after removing the unadsorbed polymer. The redispersion method is not particularly limited, and the redispersion method can be mixed and dispersed using the above-described disperser such as a paint shaker or a high-pressure homogenizer. Examples of the organic solvent used in the redispersion step include the organic solvents (c-1) and (c-2), and those shown in the organic solvent (c-1) are preferable.
Moreover, it can also re-disperse using an ultrasonic homogenizer. As a high-power ultrasonic homogenizer, SILENTSONIC UT-204 manufactured by Sharp Corporation, ultrasonic homogenizer US-300T manufactured by Nippon Seiki Seisakusho Co., Ltd., US-1200T, RUS-1200T, MUS-1200T, manufactured by Healsha Ultrasonic processor UIP series and the like. Examples of the ultrasonic irradiation method include a batch method in which stirring means such as an agitator, a magnetic stirrer, and a disper are used in combination, and a flow method in which a dispersion is sent at a constant flow rate in a chamber equipped with an ultrasonic irradiation unit. An ultrasonic homogenizer may be used in combination with the above-described paint shaker, high-pressure homogenizer, or the like.
It is preferable to perform the redispersion treatment because the contrast of the cured film using the pigment dispersion is improved. This is presumably because coarse particles that affect the decrease in contrast are atomized by redispersion.

[Pigment dispersion for color filter]
The pigment dispersion for a color filter obtained by the production method of the present invention is a pigment dispersion containing a pigment (A), a pigment dispersion polymer (B), and an organic solvent (C). The organic solvent (c-1) represented by the general formula (1) and the organic solvent (c-) represented by the general formula (2) having a viscosity at 25 ° C. of 0.3 to 1.0 mPa · s. 2), the pigment (A) is finely and stably dispersed, and as a result, the contrast of the cured film using the pigment dispersion is excellent.
The proportion of the pigment (A) in the pigment dispersion is preferably 3% by weight or more from the viewpoint of obtaining good colorability, preferably 3 to 30% by weight from the viewpoint of obtaining good colorability and viscosity, More preferred is 20% by weight.
The content of the organic solvent (C) is preferably from 100 to 3000% by weight, preferably from 200 to 1000% by weight based on the total solid content in the pigment dispersion, from the viewpoint of obtaining good colorability and good viscosity of the dispersion. % Is more preferable.

The volume median particle size (D50) of the pigment (A) in the pigment dispersion, particularly the diketopyrrolopyrrole pigment, is preferably 90 nm or less, preferably 30 to 90 nm in order to obtain a good contrast as a color material for a color filter. Is more preferable, and 40-90 nm is still more preferable.
The volume median particle size (D50) means a particle size at which the cumulative volume frequency calculated by the volume fraction becomes 50% by accumulation from the small particle size side. The volume median particle size (D50) was determined by diluting the pigment dispersion immediately after production with propylene glycol monomethyl ether acetate (PGMEA) 300 times, and using a particle size analyzer (ZETASIZER Nano-ZS, manufactured by Sysmex Corporation). As measurement conditions, for example, diketopyrrolopyrrole pigment particle refractive index: 1.51, diketopyrrolopyrrole pigment density: 1.45 g / cm ³ , PGMEA refractive index: 1.40, PGMEA viscosity: 1.081 cP Enter and measure at 20 ° C.
The viscosity (20 ° C.) at a solid content of 20% by weight of the pigment dispersion obtained by the production method of the present invention is preferably 1 to 200 mPa · s, and preferably 1 to 100 mPa · s in order to obtain a favorable viscosity as a color material for a color filter. -S is more preferable. Moreover, in order to maintain the favorable discharge property at the time of manufacturing a color filter by the inkjet method, 1-50 mPa * s is preferable and 1-30 mPa * s is more preferable.

[Coloring composition for color filter]
The coloring composition for a color filter of the present invention contains the pigment dispersion for a color filter obtained by the above-described production method, but a binder other than the pigment (A), the pigment dispersion polymer (B), and the organic solvent (C). , Polyfunctional monomer (curing component), photopolymerization initiator and the like can be contained.
Examples of binders include copolymers of (meth) acrylic acid and (meth) acrylic acid esters (for example, methacrylic acid / benzyl methacrylate copolymer), styrene / maleic anhydride copolymers, styrene / maleic anhydride copolymers. Examples include a reaction product of a polymer and alcohols. The weight average molecular weight is preferably 5,000 to 200,000. The content of the binder in the non-aqueous pigment dispersion of the present invention is preferably 20 to 80% by weight with respect to the total solid content.
As polyfunctional monomers, (meth) acrylic acid esters (for example, dipentaerythritol hexaacrylate) having two or more ethylenically unsaturated double bonds, urethane (meth) acrylates, (meth) acrylic acid amides, allyl compounds And vinyl esters. The content of the polyfunctional monomer in the pigment dispersion of the present invention is preferably 10 to 60% by weight with respect to the total solid content.
Examples of the photopolymerization initiator include aromatic ketones, lophine dimers, benzoin, benzoin ethers, and polyhalogens, and these can be used alone or in combination. For example, a combination of 4,4′-bis (diethylamino) benzophenone and 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 4- [pN, N-di (ethoxycarbonylmethyl) -2, 6-di (trichloromethyl) -s-triazine], 2-methyl-4 ′-(methylthio) -2-morpholinopropiophenone is preferred. The content of the photopolymerization initiator in the non-aqueous pigment dispersion of the present invention is preferably 0.2 to 10% by weight with respect to the total solid content.
Furthermore, a solvent such as cyclohexanone, ethyl cellosolve acetate, ethylene glycol diethyl ether, or ethyl acetate can be added from the viewpoint of adjusting the viscosity to enable uniform coating film formation and enhancing storage stability.

In the following production examples, examples and comparative examples, “parts” and “%” are “parts by weight” and “% by weight” unless otherwise specified. Measurement and evaluation of the molecular weight of the polymer and the contrast of the cured film using the pigment dispersion were performed by the following methods.
(1) Measurement of number average molecular weight (Mn) and weight average molecular weight (Mw) of a polymer Showa Denko Co., Ltd., two K-804L columns are used in series as a column, and 1 mmol / L of Farmin DM is contained as a solvent. Measurement was performed using polystyrene as a standard substance by the GPC method using chloroform.
(2) Measurement of contrast of cured film using pigment dispersion 1.00 part of pigment dispersion with pigment concentration adjusted to 10%, methacrylic acid / benzyl methacrylate copolymer (binder, molar ratio: 30/70, weight) (Average molecular weight: 14000, PGMEA solution having a solid content of 40% by weight) 0.15 parts, dipentaerythritol hexaacrylate (polyfunctional monomer: DPHA, manufactured by Nippon Kayaku Co., Ltd.) 0.046 parts, 2-methyl-4′- 0.035 part of (methylthio) -2-morpholinopropiophenone (photopolymerization initiator: Wako Pure Chemical Industries, Ltd.) and 0.474 part of PGMEA were mixed until uniform to obtain a pigment dispersion composition. The pigment dispersion composition was coated on a glass substrate with a spin coater, then allowed to stand for 6 minutes on a horizontal table, and dried on a hot plate at 80 ° C. for 3 minutes. Subsequently, the obtained coating film was irradiated with ultraviolet rays up to 30 mJ / cm ² using an ultraviolet fiber spot irradiation device (MUV-202U, manufactured by Moritex Corporation) to obtain a cured film. The contrast of the cured film was measured using a contrast measuring device (CT-1 manufactured by Aisaka Electric Co., Ltd.).

Production Example 1 (Production of pigment dispersing polymer (B))
Put 50 parts of methyl methacrylate, 25 parts of propylene glycol monomethyl ether acetate (PGMEA, organic solvent), 3.6 parts of 3-mercaptopropionic acid (chain transfer agent) in a reaction vessel equipped with a nitrogen introduction tube, and seal the nitrogen seal. The temperature was raised to 75 ° C. Next, a mixture of 200 parts of methyl methacrylate, 100 parts of PGMEA, 14.2 parts of the chain transfer agent and 2 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) (polymerization initiator) was added dropwise over 3 hours. did. Thereafter, a mixture of 100 parts of PGMEA, 0.9 part of the chain transfer agent, and 2 parts of the polymerization initiator was added dropwise over 1 hour, followed by aging for 2 hours. Next, the nitrogen introduction tube is switched to the air introduction tube, air is blown with a gas pump, 23.3 parts of glycidyl methacrylate, 7.9 parts of tetrabutylammonium bromide, 0.8 parts of p-methoxyphenol, and 35 parts of PGMEA are added, The mixture was reacted at 90 ° C. for 10 hours to obtain a methyl methacrylate macromer having a number average molecular weight of 1,600, a weight average molecular weight of 3,000, and a solid content (effective content) content of 60%.
In a reaction vessel equipped with a nitrogen introduction tube, 10 parts of PGMEA was placed, and the temperature was raised to 80 ° C. while sealing with nitrogen. The mixed liquid 263.4 of 69.1 parts, N-vinyl-2-pyrrolidone 14.4 parts, 2-hydroxyethyl methacrylate 13.8 parts, and PGMEA 120 parts as solid content methyl methacrylate macromer obtained in this reaction vessel. 2 parts of the polymerization initiator was added dropwise over 2 hours, and the reaction was further allowed to proceed for 3 hours after completion of the dropwise addition. A solution of the graft polymer (pigment dispersing polymer (B)) having a solid content (effective content) of 40% was obtained. Obtained. The number average molecular weight (Mn) of the obtained polymer was 6,800, and the weight average molecular weight (Mw) was 80,800.

Example 1 (Preparation of pigment dispersion)
735 parts of propylene glycol monomethyl ether acetate (PGMEA, organic solvent (C-1)), 315 parts of isopropyl acetate (organic solvent (C-2)) shown in Table 1, the pigment dispersion polymer obtained in Production Example 1 ( B) A mixture of 437.5 parts (175 parts as solid content) (40.0%) was mixed as a pigment with stirring at 17,000 rpm using a homomixer (Ultra Turrax, manufactured by IKA Japan Co., Ltd.). 175 parts of diketopyrrolopyrrole pigment (A) (Ciba Specialty Chemicals, Inc., CI Pigment Red 254, trade name “IRGAPHOR BK-CF”, average primary particle size 30 nm (catalog value)) The mixture was stirred and mixed for 60 minutes to obtain a primary preliminary dispersion.
The obtained mixture was mixed with 0.2 mmφ zirconia beads (filling rate 60 vol%) in a dyno mill (manufactured by Shinmaru Enterprises Co., Ltd., 0.6 L-ECM) under conditions of a stirring peripheral speed of 8 m / s and a residence time of 5 minutes. Then, three passes were processed by a continuous method to disperse coarse particles of several μm to obtain a secondary preliminary dispersion.
Next, the obtained secondary preliminary dispersion was subjected to 6-pass treatment by a continuous method at a pressure of 150 MPa with a high-pressure dispersing machine (manufactured by Microfluidics, Microfluidizer MF-110H) to obtain a tertiary preliminary dispersion.
Next, an ultra apex mill (internal volume 0.17 L, trade name, manufactured by Kotobuki Industries Co., Ltd.) filled with 0.03 mmφ zirconia beads (filling rate 64 vol%) was stirred for the tertiary preliminary dispersion at a peripheral speed of 6 m / s. Then, a 50-pass treatment was carried out by a continuous method under the condition of a residence time of 0.6 minutes to obtain a main dispersion pigment dispersion.
The obtained pigment dispersion was treated under reduced pressure of −0.08 MPa while heating to 75 ° C. with warm water using a rotary evaporator (manufactured by Tokyo Rika Co., Ltd., product name EYELA A-1000S type), and PGMEA (organic solvent (C— 1)) and isopropyl acetate (organic solvent (C-2)) were distilled off to 1% by weight or less to obtain a pigment dispersion. Table 1 shows the contrast evaluation results.

Examples 2-5 and Comparative Examples 1-3
The type and amount of the organic solvents (c-1) and (c-2) were changed as shown in Table 1, and the pigment dispersion was treated in the same manner as in Example 1 except that the treatment with the high-pressure disperser was not performed. Got the body. Table 1 shows the contrast evaluation results.
Examples 6 to 7 and Comparative Example 4
A predetermined amount of diethylene glycol monobutyl ether acetate (BCA) is used as the organic solvent (c-1), and the type and amount of the organic solvent (c-2) are changed as shown in Table 1, and the treatment with a high-pressure disperser is performed. A pigment dispersion was obtained in the same manner as in Example 1 except that no pigment dispersion was used. Table 1 shows the contrast evaluation results.

  In the table, it can be seen that the cured films using the pigment dispersions obtained in Examples 1 to 7 are extremely excellent in contrast of the cured films as compared with Comparative Examples 1 to 4.

Claims (6)

A method for producing a pigment dispersion containing a pigment (A), a pigment dispersing polymer (B), and an organic solvent (c-1) represented by the following general formula (1):
The pigment (A) contains a diketopyrrolopyrrole pigment, and the pigment-dispersing polymer (B) is obtained by a coupling reaction between the following component (b1) and the following component (b2), and has a weight average molecular weight of 5,000 to 5,000. 700,000 graft polymer for pigment dispersion, and when dispersing the pigment (A) and the pigment dispersion polymer (B), the organic solvent (c-1) and the following general formula (2) are used as the organic solvent (C). And a method for producing a pigment dispersion for a color filter, in which an organic solvent (c-2) having a viscosity at 25 ° C. of 0.3 to 1.0 mPa · s is present.
Component (b1): 5 to 95% by weight of a structural unit derived from a vinyl monomer (b1a) containing a reactive functional group and 5 to 95% by weight of a structural unit derived from a vinyl monomer (b1b) having an amide bond Polymer
Component (b2): Poly (meth) acrylate alkyl having a functional group capable of reacting with the reactive functional group of component (b1) at one end

(Wherein R ¹ and R ² each independently represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, R ³ represents a hydrogen atom or a methyl group, n represents an average number of added moles, ~ 4.)

(In the formula, R ⁴ and R ⁵ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.) The manufacturing method of the pigment dispersion for color filters of Claim 1 whose sum total of carbon number of R < ⁴ > and R < ⁵ > of the organic solvent (c-2) represented by General formula (2) is 1-6.   The manufacturing method of the pigment dispersion for color filters of Claim 1 or 2 whose boiling point in 1 atmosphere of the organic solvent (c-2) represented by General formula (2) is 30-110 degreeC.   The manufacturing method of the pigment dispersion for color filters in any one of Claims 1-3 which removes organic solvent (c-2) substantially after completion | finish of dispersion | distribution.   The manufacturing method of the pigment dispersion for color filters in any one of Claims 1-4 disperse | distributed with a high voltage | pressure disperser. The manufacturing method of the pigment dispersion for color filters in any one of Claims 1-5 whose pigment (A) is a diketopyrrolopyrrole pigment represented by the following general formula ( 3 ).

(Wherein, X ¹ and X ² each independently represent a hydrogen atom or a halogen atom, and Y ¹ and Y ² each independently represent a hydrogen atom or a —SO ₃ H group.)