JP5480584B2 - Pigment dispersion for color filters - Google Patents

Description

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

  Color filters used in liquid crystal display devices have so far been developed by applying a colored composition in which a pigment dispersion is blended with a resin or the like to a transparent substrate such as glass using a spin coater or the like, and then exposing / curing, developing, and heat curing. Lithography is used, but in recent years, production of color filters by the ink-jet method has become active from the viewpoint of productivity and downsizing of manufacturing apparatuses.

By the way, the pigment dispersion used for the color filter is a non-aqueous pigment dispersion using an organic solvent as a medium, but various copolymers are known as dispersants for favorably dispersing the pigment in the organic solvent. .
For example, Patent Document 1 discloses a pigment dispersant containing a graft copolymer having a nitrogen atom and an ether group, and a pigment including the same, in order to effectively prevent aggregation of the pigment and improve dispersibility. Dispersion compositions and colored photosensitive compositions are disclosed.
Patent Document 2 discloses a nitrogen-containing monomer having a ring structure composed only of nitrogen atoms and carbon atoms for the purpose of improving the dispersion stability of the pigment without degrading the properties such as developability. A copolymer (i) having a unit and a monomer unit having an acid group, or a nitrogen-containing monomer unit having a heteroaromatic ring structure essentially comprising a nitrogen atom and a monomer unit having an acid group A pigment dispersion composition comprising a copolymer (ii) having a pigment and a pigment is disclosed.

JP 2001-31885 A JP 2005-240000 A

Generally, in order to improve the color developability of a liquid crystal display device, it is necessary to increase the optical density of the color filter. In order to increase the optical density, it can be improved to some extent by increasing the blending concentration of the pigment in the pigment dispersion used in the color filter. However, increasing the amount of pigment increases the dispersion to maintain storage stability. It is necessary to increase the amount of the agent and the like, and there is a problem that the viscosity of the pigment dispersion increases. In the production of color filters, if the viscosity of the pigment dispersion is high, the colored composition containing the pigment dispersion becomes difficult to be ejected from the nozzle when the ink jet method is used, and when the photolithography method is used, Smoothness may not be maintained.
The present invention is a pigment dispersion for a color filter that has a low viscosity, excellent storage stability, and can obtain a cured film excellent in optical density, a coloring composition for a color filter containing the pigment dispersion, and It is an object to provide a method for producing a pigment dispersion for a color filter.

The inventors of the present invention can improve the dispersion stability of a pigment even with a small amount of polymer by using a specific combination of a polymer used for dispersing the pigment and an organic solvent, and even if the pigment concentration is high. It was found that a uniform dispersed state and a fluid state can be maintained, and as a result, the above-mentioned problems can be solved.
That is, the present invention provides the following [1] to [3].
[1] A color containing a pigment (A), a pigment-dispersing polymer (B) having a structural unit represented by the following general formula (1), and an organic solvent (C) represented by the following general formula (2) Pigment dispersion for filters.

(Wherein R ¹ and R ³ represent an alkyl group having 1 to 6 carbon atoms, R ² represents a hydrogen atom or a methyl group, A represents an alkanediyl group having 2 to 3 carbon atoms, and n represents an added mole) The number is 1 to 4. However, in the formulas (1) and (2), the corresponding R ¹ and A are the same group, and the corresponding n is the same number.)
[2] A coloring composition for a color filter comprising the pigment dispersion for a color filter according to [1].
[3] A mixture containing a pigment (A), a pigment-dispersing polymer (B) having a structural unit represented by the general formula (1), and an organic solvent (C) represented by the general formula (2) The manufacturing method of the pigment dispersion for color filters which has the process of dispersing.

  According to the present invention, a pigment dispersion for a color filter that has a low viscosity, excellent storage stability, and an excellent optical density can be obtained, and a coloring composition for a color filter containing the pigment dispersion And a method for producing a pigment dispersion for a color filter.

  The pigment dispersion for a color filter of the present invention comprises a pigment (A), a pigment dispersion polymer (B) having a structural unit represented by the following general formula (1) (hereinafter simply referred to as “pigment dispersion polymer (B)”). And an organic solvent (C) represented by the following general formula (2) (hereinafter also simply referred to as “organic solvent (C)”).

(Wherein R ¹ and R ³ represent an alkyl group having 1 to 6 carbon atoms, R ² represents a hydrogen atom or a methyl group, A represents an alkanediyl group having 2 to 3 carbon atoms, and n represents an added mole) The number is 1 to 4. However, in the formulas (1) and (2), the corresponding R ¹ and A are the same group, and the corresponding n is the same number.)
Hereafter, each component etc. which are used for this invention are demonstrated.

[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, lake pigments, and the like. 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. A copper phthalocyanine pigment such as CI Pigment Blue 15: 6; I. And polyhalogenated zinc phthalocyanine pigments such as CI Pigment Green 58.
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. Pigment azo complex pigments such as CI Pigment Yellow 150, C.I. 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 (3) is preferable from the viewpoint of more effectively expressing the effects of the present invention.

In formula (3), 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.
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.
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, for 100 particles, the minor axis diameter and major axis diameter of each primary particle are measured, and the average value is taken as the average primary particle diameter of the particles.
Said pigment (A) can be used individually or in combination of 2 or more types.

[Pigment dispersing polymer (B)]
The pigment dispersing polymer (B) used in the present invention is used to disperse the pigment (A) in an organic solvent (C) containing the compound represented by the general formula (2) in a state of being stably fined. It is done. The pigment dispersing polymer (B) has a structural unit represented by the following general formula (1).

In general formula (1), R ¹ represents an alkyl group having 1 to 6 carbon atoms, R ² represents a hydrogen atom or a methyl group, A represents an alkanediyl group having 2 to 3 carbon atoms, and n represents an added mole. The number is 1 to 4.
R ¹ is preferably an alkyl group having 2 to 5 carbon atoms, more preferably an alkyl group having 2 to 4 carbon atoms, and still more preferably a butyl group. R ² is preferably a methyl group, and A is preferably an ethylene group. n is 1-4, 1-3 are preferable and 2 is more preferable.
Examples of the pigment dispersing polymer (B) include, for example, a homopolymer composed only of the structural unit represented by the general formula (1), a graft polymer having the structural unit represented by the general formula (1) and other structural units, Copolymers (copolymers) such as block polymers or random polymers can be mentioned. In these, the graft polymer which has a structural unit represented by General formula (1) from a viewpoint of the dispersion stability of a pigment (A) is preferable.

[Graft polymer]
The graft polymer having the structural unit represented by the general formula (1) may have the structural unit represented by the general formula (1) in the main chain or in the side chain. However, from the viewpoint of maintaining low viscosity and improving optical density, it is preferable to have only in the side chain or in the side chain rather than the main chain, and only in the side chain. More preferred.
The main chain of the graft polymer preferably contains a structural unit derived from a vinyl monomer containing a nitrogen atom or a structural unit derived from a vinyl monomer containing a carboxy group, from the viewpoint of adsorptivity to the pigment (A). More preferably, it contains a structural unit derived from a vinyl monomer containing a nitrogen atom.
The side chain of the graft polymer contains a structural unit derived from an alkyl (meth) acrylate and / or a structural unit derived from styrene from the viewpoint of enhancing the dispersibility of the pigment (A) in the organic solvent (C). It is preferable that the structural unit represented by the general formula (1) is contained, and it is more preferable that the structural unit is substantially composed of only the structural unit represented by the general formula (1).
The graft polymer may be a copolymer obtained by copolymerizing another monomer copolymerizable with the monomer in any of the main chain and the side chain within a range not impairing the effects of the present invention.
In the present specification, “(meth) acrylic acid” means “acrylic acid and / or methacrylic acid”.

The weight average molecular weight of the graft polymer is preferably 1000 to 1,000,000, more preferably 2000 to 800,000, and still more preferably 5000 to 700, from the viewpoint of adsorptivity to the pigment (A) and suppression of increase in viscosity. , 000.
The weight average molecular weight of the main chain portion of the graft polymer is preferably 5,000 to 50,000, more preferably 10,000 from the viewpoint of maintaining the low viscosity of the pigment dispersion of the present invention and improving the storage stability. To 25,000, more preferably 12,000 to 23,000, and even more preferably 15,000 to 20,000.
When the weight average molecular weight of the main chain portion of the graft polymer is in the above range, the side chain portion does not drag out due to the solubility in the organic solvent (C), and the main chain portion with respect to the pigment (A). It is considered that the adsorption portion is also effectively used and the graft polymer is efficiently adsorbed to the pigment (A), so that the storage stability is improved and the viscosity is lowered.
From the viewpoint of storage stability of the pigment dispersion of the present invention, the weight average molecular weight of the side chain portion of the graft polymer is preferably 500 to 20,000, more preferably 700 to 10,000, and still more preferably 700 to 6000. is there.
The ratio of the weight average molecular weight of the main chain portion of the graft polymer to the weight average molecular weight of the side chain portion (main chain / side chain) is preferably from 1 to 4 from the viewpoint of storage stability and viscosity reduction of the pigment dispersion of the present invention. 10, More preferably, it is 2-5, More preferably, it is 3-5.
In addition, the measurement of a weight average molecular weight can be performed by the method as described in an Example.

(Monomer that is a constituent unit of the main chain)
A vinyl monomer containing a nitrogen atom is preferably used as the monomer constituting the structural unit of the main chain, and a copolymerizable monomer can be copolymerized as long as the effects of the present invention are not hindered.
As a vinyl monomer containing a nitrogen atom, a vinyl monomer having a functional group such as an amide group or an amino group is preferable. Specifically, (meth) acrylamides, vinylpyrrolidones, vinylpyridines, nitrogen-containing styrene monomers And nitrogen-containing (meth) 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 vinyl monomers containing nitrogen atoms, (meth) acrylamides and vinylpyrrolidones are preferred, and N-vinylpyrrolidone is more preferred from the viewpoint of adsorptivity to the pigment (A).
The content of the component derived from the vinyl monomer containing a nitrogen atom in all the structural units of the graft polymer is the viewpoint of adsorptivity to the pigment (A), and the viewpoint of suppressing the increase in viscosity and optimizing the dispersed particle size. Therefore, it is preferably 1 to 30% by weight, more preferably 2 to 25% by weight, still more preferably 5 to 20% by weight.

Monomers copolymerizable with vinyl monomers containing nitrogen atoms include methyl (meth) acrylate, ethyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, and isobornyl (meth) acrylate. , (Meth) acrylic acid esters such as 2-hydroxyethyl (meth) acrylate, glycerol mono (meth) acrylate, perfluorooctylethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, and styrenes such as styrene And 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 more preferable.
When using the method by the coupling reaction mentioned later as a manufacturing method of the said graft polymer, the vinyl monomer containing a reactive functional group can also be copolymerized. Specific examples of the vinyl monomer containing a reactive functional group will be described later.
The said monomer can be used individually or in combination of 2 or more types.

(Monomers that constitute side chain constituent units)
As the monomer that becomes the constituent unit of the side chain, it is preferable to use a monomer that is derived from the constituent unit represented by the following general formula (1). Can be copolymerized.

In the general formula (1), R ¹ , R ² , A and n are as described above.
The monomer from which the structure represented by the general formula (1) is derived is an alkoxy polyalkylene glycol (meth) acrylate, and specific examples include butoxydiethylene glycol (meth) acrylate, butoxydiethylene glycol methacrylate. Is preferred. As a commercial item of (meth) acrylic acid alkoxy polyalkylene glycol, Kyoeisha Chemical Co., Ltd. brand name: Light ester BC (butoxy diethylene glycol methacrylate) etc. are mentioned.
Monomers that can be copolymerized with the monomer derived from the structure represented by the general formula (1) include methyl (meth) acrylate, ethyl (meth) acrylate, stearyl (meth) acrylate, and (meth) acrylic acid. (Meth) acrylic such as benzyl, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, glycerol mono (meth) acrylate, perfluorooctylethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate Examples include acid esters. Among these, methyl (meth) acrylate, ethyl (meth) acrylate, and benzyl (meth) acrylate are preferable, and methyl (meth) acrylate is more preferable.
The said monomer can be used individually or in combination of 2 or more types.
The content of the structural unit represented by the general formula (1) in the side chain of the graft polymer is preferably 5 to 100% by weight, more preferably 50 to 100% by weight with respect to all the structural units in the side chain. %, More preferably 80 to 100% by weight.
The content of the structural unit represented by the general formula (1) in the graft polymer is preferably 40 to 80% by weight, more preferably 60 to 800% by weight, still more preferably based on all the structural units in the polymer. Is 60 to 70% by weight.

[Production of graft polymer]
The method for producing the graft polymer includes (i) a method in which a monomer that is a constituent unit of the main chain portion and a monomer that constitutes a side chain portion, a so-called macromer, and (ii) a polymer that constitutes the main chain portion. And a polymer constituting the side chain part, from the viewpoint of fine stabilization of the pigment (A), (ii) a polymer constituting the main chain part and a polymer constituting the side chain part. A method in which is coupled to each other is preferred.

(Production by coupling reaction)
The polymer constituting the main chain part used in the coupling reaction is preferably a polymer containing a constituent unit derived from a vinyl monomer containing a nitrogen atom, and contains a constituent unit derived from a vinyl monomer containing a reactive functional group. Is preferred. The polymer can be obtained by copolymerizing the monomer mixture.
Examples of the vinyl monomer containing a reactive functional group include monomers containing an epoxy group, an isocyanate group, a carboxy group, a phosphoric acid group, a sulfonic acid group, and an amino group. Is preferable, (meth) acrylic acid esters containing a glycidyl group are preferable, and glycidyl (meth) acrylate is more preferable.
When the polymer constituting the main chain part used in the coupling reaction contains an epoxy group as a reactive functional group, the epoxy value is preferably 19 to 375 mgKOH / g from the viewpoint of reactivity with the side chain part. 30 to 350 mgKOH / g is more preferable, and 40 to 300 mgKOH / g is particularly preferable.
The epoxy value can be measured by the method described in the examples.

The polymer constituting the side chain part used in the coupling reaction has a reactive functional group that reacts with the reactive functional group of the polymer constituting the main chain part at one end thereof, preferably in the general formula (1) It is a polymer containing the structural unit represented.
When the reactive functional group of the polymer constituting the main chain portion is an epoxy group, it is preferable that one end of the polymer constituting the side chain portion is a carboxy group or an amino group.
The polymer constituting the side chain part used in the coupling reaction is preferably obtained by solution polymerization using, for example, a polymerization initiator or chain transfer agent containing a carboxy group or amino group which is a reactive functional group.
The coupling reaction between the polymer constituting the side chain portion and the polymer constituting the main chain portion may be carried out under the condition that each reactive functional group sufficiently reacts. However, each polymer is contained in an organic solvent in the presence of a catalyst. It is preferable to dissolve this.
Examples of the catalyst include quaternary ammonium salts such as quaternary ammonium halides, tertiary amines such as triethylamine, alkali metal hydroxides, inorganic acids, sulfonic acids, carboxylic acids, solid acids, solid bases, and the like. . In these, a quaternary ammonium halide is more preferable and tetrabutylammonium bromide etc. are especially preferable.

[Organic solvent (C)]
The organic solvent (C) used in the present invention is an organic solvent represented by the general formula (2) from the viewpoint of maintaining low viscosity and improving optical density.

In the general formula (2), R ¹ and R ³ independently represent an alkyl group having 1 to 6 carbon atoms, A is shows the alkanediyl group having 2 to 3 carbon atoms, n represents 1 to 4. That, R ^1, A, and n, in the general formula (1) are the same as R ^1, A, and n, is the same as the range described in their preferred ranges are also the paragraph [0018].
However, in General Formula (1) and General Formula (2) in the pigment dispersion of the present invention, corresponding R ¹ and A are the same groups (for example, both are butyl groups, and both are ethylene groups), The corresponding n is also the same number (for example, both are 2).

Examples of the organic solvent (C) represented by the general formula (2) include the following (i) and (ii).
(I) Alkanediyl glycol monoalkyl ether propionate: ethylene glycol monomethyl ether propionate, ethylene glycol monoethyl ether propionate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, etc. (ii) Alkanediyl glycol monoalkyl ether acetate: ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate (BCA), etc. .
Among organic solvents (C), (i) alkanediyl glycol monoalkyl ether propionate and (ii) alkanediyl glycol monoalkyl ether acetate are preferred, (ii) alkanediyl glycol monoalkyl ether acetate is more preferred, Propylene glycol monomethyl ether acetate (PGMEA, boiling point: 146 ° C.) and diethylene glycol monobutyl ether acetate (BCA, boiling point: 247 ° C.) are more preferred, and diethylene glycol monobutyl ether acetate (BCA) is particularly preferred.
The organic solvent (C) is preferably 50 to 100% by weight of the organic solvent contained in the pigment dispersion of the present invention, more preferably 70 to 100%, and 90 to 100%. More preferably, the organic solvent contained in the pigment dispersion of the present invention is more preferably composed only of the organic solvent (C).

(Other organic solvents)
In the present invention, other organic solvents can be used in combination as long as the object of the present invention is not impaired. The other organic solvent that can be used in combination is not particularly limited, but a high-boiling organic solvent having a boiling point of 100 ° C. or higher is preferable. Examples of such a high boiling point organic solvent include the following (iii) to (v).
(Iii) Ethylene glycol alkyl ethers (cellosolves): ethylene glycol monomethyl ether, ethylene glycol diethyl ether, ethylene glycol monoethyl ether, etc. (iv) Diethylene glycol alkyl ethers (carbitols): diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol Monoethyl ether, etc. (v) Alkanediyl glycol dialkyl ethers: Propylene glycol monomethyl ether, propylene glycol dimethyl ether, etc. Among the above other organic solvents, the organic solvent represented by the general formula (2) used in the present invention (C ) And one or more values of R ¹ , A or n are different (i) alkanediyl glycol monoalkyl ether propionate And (ii) alkanediyl glycol monoalkyl ether acetate, and (ii) alkanediyl glycol monoalkyl ether acetate is more preferred.
The value of R ¹ , A or n is preferably closer to the value of the organic solvent (C) represented by the general formula (2), and the values of R ¹ and A are represented by the general formula (2). Those which are the same as (C) and have different values of n are preferred.

[Method for producing pigment dispersion]
The method for producing a pigment dispersion for a color filter of the present invention is represented by the pigment (A), the pigment dispersion polymer (B) having the structural unit represented by the general formula (1), and the general formula (2). It has the process of carrying out the dispersion process of the mixture containing the organic solvent (C) containing the compound made.
The obtained pigment dispersion for a color filter can provide a cured film having low viscosity, excellent storage stability, and excellent optical density. The reason is not clear, but it can be considered as follows.
The pigment (A) is usually finely dispersed to improve the color developability. However, the finer the pigment (A), the higher the cohesiveness and the lower the dispersion stability. Therefore, the optical density decreases due to aggregation, and a large amount of the pigment-dispersing polymer (B) is required to prevent this.
However, in the present invention, the pigment-dispersing polymer (B) and the organic solvent (C) have a common structure of C—COO (AO) n—R ¹ (R ¹ and A are the same as described above). Therefore, the common structure portion of the pigment dispersing polymer (B) and the organic solvent (C) has a high affinity, and the pigment (A) can be uniformly atomized with a small amount of the pigment dispersing polymer (B), and the stable pigment. It is believed that a dispersion is obtained. Further, the reason is not clear, but when this combination of the pigment dispersing polymer and the organic solvent is used, the viscosity of the pigment dispersion can be kept low, and even when the pigment dispersion is at a high concentration, a uniform flow state is maintained. Since it can be maintained, when cured, a stable cured film is formed, and the optical density of the color filter is excellent.
These effects are more effectively exhibited when the pigment dispersing polymer (B) is a graft polymer having a side chain having a structural unit represented by the general formula (1).

In the production method of the present invention, the dispersion treatment method is not limited, and the desired pigment dispersion may be obtained by one dispersion. However, the pigment (A), which is a powder having a large particle size, and the pigment dispersion polymer (B ), The organic solvent (C) is blended, and a pre-dispersion step is preferably performed in order to mix uniformly, and then the main dispersion step is preferably performed in order to refine the pigment.
(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, but the pigment dispersion polymer (B) and the organic solvent ( It is preferable that a premix is prepared by mixing C) in advance, and the pigment (A) is mixed and dispersed in the resulting premix to obtain a final mixture.
The weight ratio [(A) / (B)] of the pigment (A) to the pigment-dispersing polymer (B) at the time of pre-dispersion is a viewpoint for attaching a required amount of the pigment-dispersing polymer (B) to the pigment (A). Therefore, the weight ratio [(A) / (B)] is preferably 100/30 to 100/250, and more preferably 100/40 to 100/200.
The dispersion time for the preliminary dispersion is usually 0.1 to 10 hours, preferably 0.5 to 4 hours, and more preferably 1 to 3 hours.

There is no restriction | limiting in the mixing disperser used by preliminary dispersion, A well-known various disperser can be used. For example, a commonly used mixing and stirring apparatus equipped with anchor blades, and specific examples include a homomixer such as Ultra Tax (made by IKA Japan Co., Ltd., trade name), Ultra Disper, Desperm (Asada Tekko Co., Ltd., product) Name), Milder (Ebara Manufacturing Co., Ltd., Taiheiyo Kiko Co., Ltd., trade name), TK Homomixer, TK Pipeline Mixer, TK Homojetter, TK Homomic Line Flow, Filmix (and above, Primix Co., Ltd., trade name), etc. Kneading machines such as high-speed agitating and mixing equipment, roll mills, kneaders, extruders, etc., and high-pressure homogenizers such as high-pressure homogenizers (Izumi Food Machinery Co., Ltd., trade names), microfluidizers (Microfluidics, trade names) ), Nanomizer (Yoshida machine) Kogyo Co., Ltd., trade name), Optimizer, Starburst (Sugino Machine Co., Ltd.) and other chamber type high-pressure dispersers such as high-pressure homogenizers, paint shakers, bead mills, dyno mills (Shinmaru Enterprises Co., Ltd., Media-type dispersers such as trade name). A plurality of these devices can be combined.
Among these, from the viewpoint of uniformly mixing the pigment (A) in the organic solvent (C), a high-speed stirring and mixing device such as a homomixer, and a media type dispersing machine such as a paint shaker or a bead mill are preferable. It is more preferable.

(This dispersion process)
This dispersion step is performed in order to further refine the mixture obtained by the above preliminary dispersion. From the viewpoint of refining the pigment (A), it is preferable to use a media type disperser, You may use a disperser together.
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 obtained pigment 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. For example, when the disperser is a paint shaker, cooling is preferably performed using a spot cooler that blows cold air. When the disperser is a bead mill, kneader, or high-pressure disperser, cooling is preferably performed by flowing a coolant through a jacket.
The dispersion time of this dispersion is preferably 3 to 200 hours, more preferably 5 to 50 hours, from the viewpoint of sufficiently miniaturizing the pigment (A).

Further, the pigment dispersing 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) to the pigment dispersing polymer (B) at the end of the dispersion is 100/30 to 100/250 from the viewpoint of reducing the viscosity of the dispersion. Preferably, 100 / 40-100 / 200 is more preferable.

The pigment dispersion obtained by the present dispersion step can be used as it is as a raw material for the coloring composition for a color filter of the present invention, but it is preferable to further perform the following steps.
From the viewpoint of improving the optical density of the cured film and improving the storage stability of the pigment dispersion, the pigment dispersion obtained in this dispersion step is centrifuged and coarse particles are removed by removing the sediment. It is preferable to do.
Further, from the viewpoint of reducing the viscosity of the pigment dispersion and improving the storage stability, it is preferable to remove the pigment dispersion polymer (B) not adsorbed on the pigment. To remove the pigment dispersion polymer (B) that is not adsorbed on the pigment, the polymer molecules are separated from the pigment particles by ultrafiltration, the pigment particles are precipitated by centrifugation, and the polymer remaining in the supernatant is removed. The method by centrifugation is preferable because of its high removal efficiency.
Furthermore, from the viewpoint of improving the optical density of the cured film and improving the storage stability of the pigment dispersion, it is preferable to redisperse the dispersion or sediment obtained by ultrafiltration or centrifugation with a disperser. As the disperser used for redispersion, the above dispersers can be used, but an ultrasonic disperser is preferable.
The weight ratio [(A) / (B)] of the pigment (A) and the pigment dispersing polymer (B) in the pigment dispersion after removing the pigment dispersing polymer (B) not adsorbed on the pigment is the pigment From the viewpoint of lowering the viscosity of the dispersion and storage stability, 100/40 to 100/120 is preferable, and 100/50 to 100/80 is more preferable.

[Pigment dispersion for color filter]
The pigment dispersion for a color filter obtained by the production method of the present invention contains a pigment (A), a pigment dispersion polymer (B), and an organic solvent (C).
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 weight ratio [(A) / (B)] of the pigment (A) and the pigment dispersing polymer (B) in the pigment dispersion is 100/40 to 100/120 from the viewpoint of storage stability of the pigment dispersion. Preferably, 100 / 50-100 / 80 is more preferable.
The content of the organic solvent (C) in the pigment dispersion is preferably 20 to 90% by weight, more preferably 40 to 80% by weight from the viewpoints of good colorability, low viscosity of the dispersion, and improved stability. .
The weight ratio [(A) / (C)] of the pigment (A) and the organic solvent (C) in the pigment dispersion is 100/100 from the viewpoints of good colorability, low viscosity of the dispersion and improved stability. 500-100 / 650 are preferable and 100 / 500-100 / 515 are more preferable.
The weight ratio [(B) / (C)] of the pigment dispersion polymer (B) and the organic solvent (C) in the pigment dispersion is from the viewpoint of lowering the viscosity and improving the stability of the dispersion of the pigment dispersion. 100/670 to 100/1100 is preferable, and 100/880 to 100/1010 is more preferable.

The volume median particle size (D50) of the pigment (A) in the pigment dispersion is preferably 80 nm or less, more preferably 20 to 70 nm, and more preferably 20 to 60 nm in order to obtain a good contrast ratio as a color filter color material. Is 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 300 times with diethylene glycol monobutyl ether acetate (BCA) and using a particle size analyzer (ZETASIZER Nano-ZS, manufactured by Sysmex Corporation). As the measurement conditions, for example, in the case of a diketopyrrolopyrrole pigment, pigment particle refractive index: 1.51, pigment density: 1.45 g / cm ³ , BCA refractive index: 1.426, BCA viscosity: 3.60 cP are input. And it can measure at 20 degreeC.
The viscosity (20 ° C.) at a solid content of 12% 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 of the present invention, and can contain a binder component, a surfactant and the like in addition to the pigment dispersion of the present invention.
Examples of the binder component include (i) a binder component composed of an ionizing radiation curable component, and (ii) a binder component composed of a thermopolymerizable curable component.
(I) The binder component consisting of an ionizing radiation curable component is mainly composed of a resin, and if necessary, preferably contains a polyfunctional monomer or a photopolymerization initiator activated by ionizing radiation, and further a polyfunctional oligomer, A monofunctional monomer, a sensitizer, and the like can be blended. These resins, oligomers, monomers, additives and the like can be used alone or in combination of two or more.
(I) The content of the binder component comprising the ionizing radiation curable component is preferably 20 to 80% by weight in the effective component excluding the solvent, and the content of the photopolymerization initiator is 0.00 in the effective component excluding the solvent. 2 to 20% by weight is preferred.

(I) As a constituent resin of the binder component composed of an ionizing radiation curable component, any of a non-polymerizable resin having no polymerization reactivity itself and a resin having a polymerization reactivity in itself may be used. Non-polymerizable resins are preferred.
Examples of the non-polymerizable resin include acrylic acid, methacrylic acid, trimellitic acid, methyl acrylate, caprolactone, methyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, benzyl acrylate, benzyl methacrylate, styrene, polystyrene macromonomer, And a copolymer composed of two or more monomers selected from polymethyl methacrylate macromonomers. More specifically, methacrylic acid / benzyl methacrylate copolymer, methacrylic acid / benzyl methacrylate / styrene copolymer, benzyl methacrylate / styrene copolymer, benzyl methacrylate macromonomer / styrene copolymer, benzyl methacrylate / styrene macromonomer Examples thereof include a copolymer, a styrene / maleic anhydride copolymer, and a reaction product of a styrene / maleic anhydride copolymer and an alcohol. The weight average molecular weight of the non-polymerizable resin is preferably 5,000 to 200,000.

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 in the effective component excluding the solvent.
Examples of the photopolymerization initiator include aromatic ketones, lophine dimers, benzoin, benzoin ethers, polyhalogens and the like. 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.

(Ii) The binder component composed of a thermopolymerizable curable component is mainly composed of a resin, and may contain a polyfunctional epoxy compound, a polyvalent carboxylic acid curing agent, and a catalyst for promoting thermal polymerization as necessary. preferable. These resins, polyfunctional epoxy compounds, polyvalent carboxylic acid curing agents, catalysts and the like can be used alone or in combination of two or more.
(Ii) The content of the binder component composed of a thermally polymerizable functional group is preferably 10 to 60% by weight in the effective component excluding the solvent.
Examples of the resin having a thermally polymerizable functional group include glycidyl (meth) acrylate, glycidyl α-ethyl acrylate, glycidyl α-n-propyl acrylate, glycidyl α-n-butyl acrylate, and epoxybutyl (meth) acrylate. , (Meth) acrylates such as epoxypentyl (meth) acrylate, epoxyheptyl (meth) acrylate; vinyl glycidyl ethers; diglycidyloxystyrenes; vinyl pyrogallol triglycidyl ethers; dihydroxymethylstyrene diglycidyl ethers; Examples include homopolymers or copolymers of monomers containing an ethylenically unsaturated bond selected from trihydroxymethylstyrene triglycidyl ethers and an epoxy group.
Furthermore, a solvent such as cyclohexanone, ethyl cellosolve acetate, ethylene glycol diethyl ether, and 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, “%” means “% by weight” unless otherwise specified.
The weight average molecular weight, non-volatile content, main chain epoxy value, pigment dispersion viscosity, volume median particle size (D50), and cured film optical density of the polymer for pigment dispersion obtained in the production example were measured. The following method was used.

(1) Measurement of weight average molecular weight (Mw) of polymer for dispersing pigment, main chain portion and side chain portion As a column, two K-804L columns manufactured by Showa Denko KK were used in series, and 1 mmol / L as a solvent. The weight average molecular weight was measured using polystyrene as a standard substance by gel permeation chromatography (GPC) method using chloroform containing dimethyl laurylamine (manufactured by Kao Corporation, Pharmin DM2098).
(2) Measurement of Non-volatile Content of Pigment Dispersing Polymer Weigh about 10 g of glass rod and dry anhydrous sodium sulfate in a petri dish, put about 2 g of polymer solution into it, mix with glass rod, -75 kPa) for 12 hours. The weight after drying was measured, and the value obtained from the following formula was defined as the nonvolatile content.
Nonvolatile content = {[sample amount− (weight after drying− (petri dish + glass rod + weight of anhydrous sodium sulfate))] / sample amount} × 100
(3) Measurement of Epoxy Value of Pigment Dispersing Polymer Hydrochloric acid was added to the polymer solution, and the amount consumed by chlorohydrinization was expressed in mg of potassium hydroxide.

(4) Measurement of Viscosity of Pigment Dispersion After holding 1 mL of a dispersion adjusted to a pigment concentration of 15% at 20 ° C. for 5 minutes, an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., model: Viscometer TV-22, rotor) 1 ° 34 ′ × R24), the viscosity of the pigment dispersion was measured at 20 ° C. and a rotation speed of 20 rpm.
(5) Measurement of volume median particle diameter (D50) The prepared pigment dispersion was diluted 300 times with diethylene glycol monobutyl ether acetate (BCA), and a particle size analyzer (manufactured by Sysmex Corporation, trade name: Zetasizer Nano ZS) was used. As the measurement conditions, the particle refractive index of diketopyrrolopyrrole pigment: 1.51 and its density: 1.45 g / cm3, the refractive index of BCA: 1.426 and its viscosity: 3.60 cP are input. , Measured at 20 ° C.
(6) Measurement of optical density of cured film using pigment dispersion After coloring compositions prepared in Examples 7 to 12 and Comparative Example 2 were applied on a glass substrate with a spin coater (800 rpm × 10 seconds), water The plate was allowed to stand for 5 minutes on a flat table and dried on a hot plate at 80 ° C. for 15 minutes. Next, the film was heated in a clean oven at 200 ° C. for 30 minutes, and further heated in a clean oven at 240 ° C. for 30 minutes to perform post-baking (baking), thereby producing a cured film. The value of x of the cured film was measured using a spectroscopic color difference meter (Nippon Denshoku Industries Co., Ltd., SE-2000 type).
(7) Storage Stability of Dispersion The pigment dispersion obtained in Examples 2 to 6 and Comparative Example 1 was filled in a glass sealed container, and the dispersion viscosity after storage at 40 ° C. for 168 hours was measured using an E-type viscometer ( The viscosity was measured at 25 ° C. using Toki Sangyo Co., Ltd. (RE80L), and the viscosity change rate was determined from the following formula. The smaller the absolute value of the change rate, the better the storage stability.
Storage stability (Viscosity change rate) (%) = (([viscosity after storage] − [viscosity before storage]) / [viscosity before storage]) × 100

Production Example 1-1 [Synthesis of Poly (N-vinyl-2-pyrrolidone / 2-hydroxyethyl methacrylate / glycidyl methacrylate)] (Synthesis of Main Chain Part of Graft Polymer)
As shown in Table 1, a monomer solution and an initiator solution were added to a separable flask equipped with a reflux condenser, a thermometer, a nitrogen introduction tube, and a stirring device, and reacted.
That is, 147.6 g of the monomer solution 1 was charged to perform nitrogen substitution, and 27.3 g of the initiator solution 1 was added while stirring at 77 ° C. Next, 318.7 g of the monomer solution 2 and 78.0 g of the initiator solution 2 were simultaneously added dropwise from another charging port over 90 minutes while stirring at 77 ° C. After completion of the dropwise addition, 129.3 g of the monomer solution 3 and 31.2 g of the initiator solution 3 were simultaneously added dropwise from another charging port over 3 hours. After completion of the dropwise addition, 18.3 g of initiator solution 4 was added, and the mixture was further stirred at 77 ° C. for 1 hour. Thereafter, 18.3 g of initiator solution 5 was added, and the mixture was further stirred at 77 ° C. for 1 hour. Thereafter, 100.0 g of ethanol was added and cooled to obtain an ethanol solution (polymer solution (1-1)) of poly (N-vinyl-2-pyrrolidone / 2-hydroxyethyl methacrylate / glycidyl methacrylate). The polymer had a weight average molecular weight of 17,300, a non-volatile content of 36.4%, and an epoxy value of 23.8 mgKOH / g.

Production Examples 1-2 to 1-6 [Poly (N-vinylpyrrolidone / 2-hydroxyethyl methacrylate / glycidyl methacrylate)] (Synthesis of main chain portion of graft polymer)
The same operation as in Production Example 1-1 was performed except that the conditions shown in Table 1 were changed in Production Example 1-1, and poly (N-vinyl-2-pyrrolidone / 2-hydroxyethyl methacrylate / glycidyl methacrylate). ) Ethanol solution (polymer solutions (1-2) to (1-6)). The results are shown in Table 1.

Production Example 1-7 [Poly (glycidyl methacrylate / 2-hydroxyethyl methacrylate / N-vinylpyrrolidone) (synthesis of main chain portion of graft polymer)
In Production Example 1-1, the procedure was changed to the conditions shown in Table 1, and further, Monomer Solution 2 and Initiator Solution 2, and Monomer Solution 3 and Initiator Solution 3 were mixed in advance and added dropwise, respectively, Production Example 1-1 The same operation was performed to obtain an ethanol solution (polymer solution (1-7)) of poly (N-vinyl-2-pyrrolidone / 2-hydroxyethyl methacrylate / glycidyl methacrylate). The results are shown in Table 1.

Production Example 2-1 [Synthesis of poly (butoxydiethylene glycol methacrylate)] (Synthesis of side chain portion of graft polymer)
A separable flask equipped with a reflux condenser, a thermometer, a nitrogen gas inlet tube and a stirrer was equipped with butoxydiethylene glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Ester BC, purity 97.8%, hereinafter “BDGM”. 150 g, 3-mercaptopropionic acid (chain transfer agent) 8.6 g, diethylene glycol monobutyl ether acetate (manufactured by Daicel Chemical Industries, Ltd., trade name: butyl diglycol acetate, purity 100%, hereinafter referred to as “BCA”) 75 .2 g were charged and the atmosphere was purged with nitrogen. Then, while stirring at 77 ° C., a solution in which 600 g of BDGM, 34.6 g of 3-mercaptopropionic acid and 181 g of BCA were mixed, and V-65 (2,2′-azobis (2, 4-dimethylvaleronitrile) (manufactured by Wako Pure Chemical Industries, Ltd., A solution prepared by mixing 6.0 g of azo polymerization initiator (trade name) and 120 g of BCA was added dropwise over 3 hours, and further stirred at 77 ° C. for 1 hour, and then a mixed solution of 1.5 g of V-65 and 20 g of BCA was added. In addition, the mixture was further stirred for 1 hour at 77 ° C. After that, a mixed solution of 1.5 g of V-65 and 20 g of BCA was added, and the mixture was further stirred for 1 hour at 77 ° C. to be a BCA solution of terminal carboxylic acid type polybutoxydiethylene glycol methacrylate. The polymer solution had an acid value of 17.7 mgKOH / g, a weight average molecular weight of 3,300, and a nonvolatile content of 62.2%.

Production Example 2-2 [Synthesis of poly (butoxydiethylene glycol methacrylate)] (Synthesis of side chain portion of graft polymer)
Into a separable flask equipped with a reflux condenser, a thermometer, a nitrogen gas inlet tube, and a stirrer was charged 150 g of BDGM, 5.8 g of 3-mercaptopropionic acid (chain transfer agent), and 73.9 g of BCA, and then purged with nitrogen. While stirring at 77 ° C., a solution in which 600 g of BDGM, 23.0 g of 3-mercaptopropionic acid, and 175 g of BCA, and a solution in which 6.0 g of V-65 and BCA were mixed were added dropwise over 3 hours. Then, it carried out similarly to manufacture example 2-1, and obtained the BCA solution (polymer solution (2-2)) of terminal carboxylic acid type polybutoxy diethylene glycol methacrylate. The acid value of the polymer solution was 12.3 mgKOH / g, the weight average molecular weight was 4,500, and the nonvolatile content was 63.7%.

Production Example 2-3 [Synthesis of polymethyl methacrylate] (Synthesis of side chain portion of graft polymer)
A separable flask equipped with a reflux condenser, a thermometer, a nitrogen gas inlet tube and a stirrer was charged with 700 g of methyl methacrylate (hereinafter referred to as “MMA”), 49.8 g of 3-mercaptopropionic acid, and 350 g of BCA, and replaced with nitrogen. Then, with stirring at 77 ° C., a solution in which 2800 g of methyl methacrylate, 199.1 g of 3-mercaptopropionic acid, 1400 g of BCA, and 28 g of V-65 were added dropwise over 3 hours. Further, a solution prepared by mixing 28 g of V-65, 12.6 g of 3-mercaptopropionic acid and 1400 g of BCA was added dropwise over 1 hour. Furthermore, it stirred at 77 degreeC for 2 hours, and obtained the BCA solution (polymer solution (2-3)) of polymethylmethacrylate. The acid value of the solution was 20 mgKOH / g, the weight average molecular weight was 3000, and the non-volatile content was 53%.

Production Example 3-1 [Production of Graft Polymer]
In a separable flask equipped with a reflux condenser, a thermometer, and a stirrer, 94.7 g of the polymer (1-1) solution of Production Example 1-1 and 89.3 g of the polymer solution (2-1) of Production Example 2-1. Then, 2.3 g of tetrabutylammonium bromide (TBAB) (catalyst) and 75.0 g of methanol were charged and stirred in an oil bath at 95 ° C. for 10 hours. Then, after adding 60 g of BCA, a moisture quantification receiver was attached, and methanol and ethanol in the system were distilled off. After almost removing methanol and ethanol, the moisture quantification receiver was removed and the reaction was continued under the same conditions. After 19.5 hours from the start of the reaction, 80 g of BCA was added and cooled, and the remaining solvent was distilled off with an evaporator (bath temperature 63 ° C., pressure 92 kPa) to obtain a graft polymer solution (3-1). The weight average molecular weight was 55,400, and the nonvolatile content was 35.4%. The reaction rate obtained from the acid value of the one-end carboxylic acid type side chain used in the reaction and the acid value of the obtained graft polymer solution was 97%. Table 2 shows the graft polymer composition and other physical properties obtained by calculation from the charged composition and the reaction rate.

Production Examples 3-2 to 3-6 [Production of Graft Polymer]
Except having changed into the conditions shown in Table 2 in manufacture example 3-1, operation similar to manufacture example 3-1 was performed and the graft polymer solution (3-2)-(3-6) was obtained. The results are shown in Table 2.

Production Example 3-7 [Production of Graft Polymer]
71.3 g of the polymer solution (1-7) of Production Example 1-7 and 98.7 g of the polymer solution (2-3) of Production Example 2-3 in a separable flask equipped with a reflux condenser, a thermometer, and a stirring device. , 39.3 g of BCA, 39.3 g of ethanol, and 2.7 g of TBAB were charged and stirred at 90 ° C. for 13 hours. After cooling, ethanol was distilled off with an evaporator to obtain a graft polymer solution (3-7). The weight average molecular weight was 28,000, and the non-volatile content was 50%. The reaction rate determined from the acid value of the one-end carboxylic acid type side chain used in the reaction and the acid value of the obtained graft polymer solution was 99%. Table 2 shows the graft polymer composition and other physical properties obtained by calculation from the charged composition and the reaction rate.

Example 1 (Production of pigment dispersion)
63.6 g of the graft polymer solution obtained in Production Example 3-1 and 71.4 g of BCA were weighed and mixed in a 500 cc polybin, and 300 g of zirconia beads having a diameter of 0.3 mm and C.I. I. 15 g of Pigment Red 254 (Toyo Ink Manufacturing Co., Ltd., LIONOGEN RED LX-8318) was added, and the mixture was shaken with a paint shaker (Asada Iron Works Co., Ltd.) for 3 hours. The zirconia beads were filtered with a stainless wire mesh (200 mesh) to obtain a preliminary dispersion.
100 g of the obtained pre-dispersion and 100 g of zirconia beads having a diameter of 0.05 mm were weighed into a 250 cc plastic bottle and shaken with the paint shaker for 24 hours. The zirconia beads were filtered with a stainless steel wire mesh (400 mesh), put into a 100 ml screw tube, and treated in an ultrasonic cleaner (manufactured by ASONE Corporation, trade name: Sefi) at 10 ° C. for 15 hours. The ultrasonically treated dispersion was centrifuged at 15500 rpm for 1 hour using a rotor (manufactured by Sigma, trade name: Sigma 3K30C) using a rotor 12158H. A dispersion obtained by adding 40 g of BCA to 20 g of the obtained supernatant and mixing the mixture was centrifuged at 25000 rpm for 24 hours using the rotor 12159H, and the supernatant was removed. BCA was added to the obtained precipitate so that the pigment concentration became 15%, and then redispersed in the ultrasonic cleaner to obtain a pigment dispersion. The results are shown in Table 3.
The solid content (%) in the dispersion composition ratio shown in Table 3 is the amount of the graft polymer charged in the dispersion step with the solid content in the supernatant removed by centrifugation (residue dried in an oven at 90 ° C.). Calculated as subtracted from

Examples 2 to 6, Comparative Examples 1 and 3 (Production of pigment dispersion)
A pigment dispersion was obtained in the same manner as in Example 1 except that the graft polymer solution, polymer solution amount, and BCA amount used in Example 1 were changed to those shown in Table 3. . The results are shown in Table 3.

Comparative Example 2 (Production of pigment dispersion)
80 parts of the pigment dispersion obtained in Comparative Example 1 and 20 parts of BCA were mixed to obtain a pigment dispersion. The results are shown in Table 3.

Production Example 4 (Production of binder solution)
(1) Synthesis of Binder Epoxy Compound 40.7 parts of BCA was charged into a four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a dropping funnel, and heated with stirring to 75 ° C. Subsequently, 54.7 parts by weight of a mixture obtained by mixing 10 parts of GMA, 40 parts of MMA, and 4.7 parts of V-65 at a temperature of 75 ° C. was dropped at a constant rate from a dropping funnel over 2 hours. After completion of the dropwise addition, 4.6 parts by weight of a mixture consisting of 0.30 part of V-65 and 4.3 parts of BCA was added, and the reaction was terminated at a temperature of 75 ° C. for 2 hours. Obtained.
(2) Preparation of Binder Solution In a beaker, 37.5 parts of the binder-type epoxy compound BCA solution of Production Example 1 (solid content 50%), polyfunctional epoxy resin (trade name: jER157S70, manufactured by Japan Epoxy Resin Co., Ltd.) 5 parts, neopentyl glycol glycidyl ether 6.25 parts, trimellic acid n-propyl vinyl ether reaction product (1/3 (mol)) BCA solution (solid content 80%) 15.63 parts, BCA 28.13 parts The mixture was stirred with a magnetic stirrer and filtered to obtain a binder solution (solid content 50%).

Examples 7 to 12 and Comparative Examples 4 to 6 (Production of colored composition)
75 parts of the pigment dispersion obtained in Examples 1 to 6 and Comparative Examples 1 to 3, 25 parts of a binder solution (solid content 50%), and 50 parts of BCA were mixed until uniform to obtain a colored composition. The results are shown in Table 4 together with a part of Table 3.

  From Table 4, it can be seen that the pigment dispersions obtained in Examples 1 to 6 have low viscosity and good storage stability, and the colored compositions obtained in Examples 7 to 12 containing the dispersions. It can be seen that the product gives a cured film having a further excellent optical density.

Claims (9)

Color filter pigment containing pigment (A), pigment dispersion polymer (B) having a structural unit represented by the following general formula (1), and organic solvent (C) represented by the following general formula (2) Dispersion.

(Wherein R ¹ and R ³ represent an alkyl group having 1 to 6 carbon atoms, R ² represents a hydrogen atom or a methyl group, A represents an alkanediyl group having 2 to 3 carbon atoms, and n represents an added mole) The number is 1 to 4. However, in the formulas (1) and (2), the corresponding R ¹ and A are the same group, and the corresponding n is the same number.)   The pigment dispersion for a color filter according to claim 1, wherein the organic solvent (C) is 50 to 100% by weight of the organic solvent contained in the pigment dispersion.   The pigment dispersion for a color filter according to claim 1 or 2, wherein the pigment dispersion polymer (B) is a graft polymer.   The pigment dispersion for a color filter according to claim 3, wherein the graft polymer has a structural unit represented by the general formula (1) in the side chain.   The pigment dispersion for a color filter according to claim 3 or 4, wherein the graft polymer has a structural unit derived from a monomer containing a nitrogen atom in the main chain.   The pigment dispersion for a color filter according to any one of claims 3 to 5, wherein the weight average molecular weight of the main chain portion of the pigment dispersion polymer (B) is 12,000 to 23,000. The pigment dispersion for a color filter according to claim 1, wherein R ¹ in the general formula (1) is a butyl group and A is an ethylene group.   The coloring composition for color filters containing the pigment dispersion for color filters in any one of Claims 1-7. Dispersing a mixture containing a pigment (A), a pigment dispersion polymer (B) having a structural unit represented by the following general formula (1), and an organic solvent (C) represented by the following general formula (2) The manufacturing method of the pigment dispersion for color filters which has the process to carry out.

(Wherein R ¹ and R ³ represent an alkyl group having 1 to 6 carbon atoms, R ² represents a hydrogen atom or a methyl group, A represents an alkanediyl group having 2 to 3 carbon atoms, and n represents an added mole) The number is 1 to 4. However, in the formulas (1) and (2), the corresponding R ¹ and A are the same group, and the corresponding n is the same number.)