JP5966534B2 - Color filter copolymer, pigment dispersion and resist composition - Google Patents

Description

  The present invention relates to a color filter copolymer, a pigment dispersion, and a resist composition.

  One industrial field in which pigments are widely used is the field of color filters. The color filter is one of the members constituting the color liquid crystal display, and is formed by forming each pattern of three primary colors of black matrix and RGB (red, green, blue) on the glass substrate surface. Each pattern of RGB is formed by a photolithography method using a resist composition containing a pigment, an alkali-soluble resin, a photosensitive compound, a photopolymerization initiator, a solvent, and the like.

  In the field of color filters, in order to achieve high contrast of an image displayed on a color liquid crystal display, the pigment is miniaturized (see Patent Document 1). In the field of color filters, there is an increasing demand for shortening the development time in the development process of the photolithography method with the aim of reducing the cost and improving the manufacturing stability as well as increasing the contrast of the image. On the other hand, the alkali-soluble resin contained in the resist composition has a function as a binder in a color filter and has a great influence on developability, and thus various proposals have been made.

  For example, a structure derived from a (meth) acrylic acid ester having a benzene ring in the main chain which is a copolymer including a structural unit derived from a vinyl monomer having a nitrogen atom and a structural unit derived from a vinyl monomer having a reactive functional group A graft copolymer in which a side chain that is a copolymer containing units is bonded has been proposed (see Patent Document 2). N-vinyl pyrrolidone is mentioned as a vinyl monomer which has a nitrogen atom. Moreover, isobornyl (meth) acrylate is mentioned as a copolymerizable monomer other than the above in the main chain.

  In addition, one or more unsaturated ethylenic monomers selected from unsaturated carboxylic acid esters, aromatic vinyls, unsaturated ethers, N-vinyl tertiary amines, unsaturated imides and maleic anhydrides, Step P obtained by polymerization by a thermal polymerization method using a thermal polymerization initiator and a molecular weight regulator which is a thiol compound having a carboxylic acid structure at the end to obtain a product having an acid group at one end; Reacting the product having an acid group at one end with a methacrylic monomer or an acrylic monomer having an epoxy structure at the end to produce a macromonomer; the macromonomer and acid group obtained in step Q; There has been proposed an alkali-soluble resin produced by a method comprising the step R of polymerizing a monomer to be contained (see Patent Document 3). Here, isobornyl (meth) acrylate is illustrated as unsaturated carboxylic acid ester used at the process P. FIG. Examples of N-vinyl tertiary amines include N-vinyl pyrrolidone. (Meth) acrylic acid is exemplified as the monomer containing an acid group used in step R.

  However, the alkali-soluble resin specifically shown in Patent Document 3 is composed of a structural unit derived from N-phenylmaleimide, a structural unit derived from styrene, a structural unit derived from 3-mercaptopropionic acid, and a structural unit derived from glycidyl methacrylate. And an alkali-soluble resin obtained by polymerizing benzyl methacrylate, methacrylic acid, and 3-mercaptopropionic acid.

  In addition, as in Patent Documents 2 and 3, the conventional proposals are exclusively aimed at improving the alkali-soluble resin. By combining a pigment, in particular, a finer pigment and the alkali-soluble resin, a high contrast is achieved. Proposals that attempt to achieve the improvement and developability are not recognized.

JP 2009-263501 A JP 2010-275536 A Special table 2010-540240 gazette

  An object of the present invention is to provide a copolymer for a color filter that is useful for increasing the contrast of an image displayed on a color liquid crystal display and can shorten the development time of a resist composition, a pigment dispersion using the copolymer, and the It is to provide a resist composition comprising a pigment dispersion.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have used a pigment, particularly a finer pigment, in combination, thereby increasing the contrast of an image displayed on a color liquid crystal display and a resist composition. The present inventors have found a copolymer that is a specific alkali-soluble resin that can simultaneously reduce the development time of the product. In addition, the present inventors mixed a pigment and the copolymer to obtain a pigment having a coating layer containing the copolymer on its surface, and using this to prepare a pigment dispersion, It has been found that the effect of contributing to high contrast of the copolymer and shortening of the development time is further improved.
The present inventors have completed the present invention based on these findings.

That is, this invention provides the following copolymer for color filters, a pigment dispersion, its manufacturing method, and a resist composition .

[ 1 ] A polymer block containing a structural unit derived from an acrylate ester and a structural unit derived from acrylic acid, a structural unit derived from N-vinylpyrrolidone, or a structural unit derived from N-vinylpyrrolidone and a structural unit derived from acrylic acid, a polymer block containing, Ri block copolymer der consisting have a weight average molecular weight of 5,000 to 20,000, and color filters for copolymer having an acid value of 30 to 200 mgKOH / g.

[ 2 ] The color filter copolymer according to [1 ] , wherein the acrylic ester is an acrylic ester having an alicyclic hydrocarbon group.

[ 3 ] A coating layer containing a pigment, a pigment dispersant, the color filter copolymer of the above [1] or [2] and a solvent, wherein the pigment contains the color filter copolymer on at least a part of the surface thereof. A pigment dispersion having:

[ 4 ] A method for producing a pigment dispersion according to [ 3 ], wherein the pigment and the color filter copolymer according to [1] or [2] are kneaded (1);
A step (2) of drying and / or pulverizing the kneaded product obtained in step (1) to obtain a pigment having a coating layer containing the color filter copolymer on its surface;
And a step (3) of obtaining a pigment dispersion by mixing a pigment having the coating layer on the surface thereof, a pigment dispersant and a solvent.

[ 5 ] In the step (1), the pulverized sodium sulfate is kneaded together with the pigment and the color filter copolymer of the above [1] or [2] , and in the step (2), the kneaded product obtained in the step (1). A pigment having a coating layer containing a color filter copolymer on its surface, by mixing the product and water, separating the solid from the resulting aqueous slurry, drying and / or pulverizing the obtained solid [ 4 ] The method for producing a pigment dispersion according to [ 4 ].
[ 6 ] A resist composition comprising the pigment dispersion of [ 3 ] above and a photosensitive compound.

  According to the present invention, a color useful for increasing the contrast of an image displayed on a color liquid crystal display and shortening the development time of a resist composition when it is applied to the surface of a pigment, particularly a refined pigment. A filter copolymer is provided. A color filter that can contribute to high image contrast while shortening the development process by using a resist composition comprising a pigment dispersion containing the pigment and the color filter copolymer of the present invention. Can be obtained.

[Copolymer for color filter]
The copolymer for a color filter of the present invention includes, as a structural unit, a structural unit derived from an acrylate ester (hereinafter referred to as “acrylic acid ester unit”), a structural unit derived from acrylic acid (hereinafter referred to as “acrylic acid unit”). And a structural unit derived from N-vinylpyrrolidone (hereinafter referred to as “N-vinylpyrrolidone unit”). Furthermore, the copolymer for a color filter of the present invention is derived from a compound having a polymerizable double bond copolymerizable with each of the above units within a range that does not impair the effects of increasing the contrast and improving the developability. Units may be included. Such structural units are derived from acrylate compounds having an alkyl moiety of 12 to 18 such as styrene, lauryl acrylate and stearyl acrylate, acrylate compounds having an aromatic hydrocarbon group such as benzyl acrylate, and the like. Valent structural unit.

  The copolymer for a color filter of the present invention is, for example, kneaded with a pigment, and dried and / or pulverized to obtain a coating layer by adhering to the pigment surface. This coating layer is formed on at least a part of the pigment surface and may be formed on the entire pigment surface. Thus, even if the coating layer containing the color filter copolymer of the present invention is formed on the pigment surface, the dispersibility of the pigment in the pigment dispersion is hardly lowered. The color filter copolymer of the present invention is considered to function as, for example, a pigment surface treatment agent.

  The copolymer for a color filter of the present invention comprises a polymer block (X) containing an acrylate ester unit and an acrylic acid unit, an N-vinylpyrrolidone unit or an N- from the viewpoint of increasing contrast and improving developability. A block copolymer comprising a polymer block (Y) containing a vinylpyrrolidone unit and an acrylic acid unit is preferred.

  In this block copolymer, the content ratio of the polymer block (X) and the polymer block (Y) is not particularly limited, but the polymer block (X) is preferably 40 to 80% by weight of the total amount of the block copolymer. More preferably, it may be 45 to 75% by weight of the total amount of the block copolymer, and the remainder may be the polymer block (Y). Thereby, effects such as improvement in pigment dispersibility in the pigment dispersion and developability of the resist composition can be obtained. The proportion of each unit in the polymer blocks (X) and (Y) is the content ratio of the polymer block (X) and the polymer block (Y) in the color filter copolymer of the present invention, and What is necessary is just to select suitably according to the content rate of each unit in the copolymer for color filters of this invention mentioned later.

  An acrylate unit is a divalent group derived from an acrylate ester. As the acrylate ester, any of those conventionally used for the synthesis of alkali-soluble resins can be used, but an acrylate ester having an alicyclic hydrocarbon group is preferred from the viewpoint of increasing the contrast and improving the developability. Examples of the acrylate ester having an alicyclic hydrocarbon group include cycloalkyl acrylate esters such as cyclopentyl acrylate and cyclohexyl acrylate, and isobornyl acrylate. Among these, isobornyl acrylate is more preferable. An acrylic ester can be used individually by 1 type or in combination of 2 or more types.

  The acrylic acid unit is a divalent group derived from acrylic acid. The N-vinylpyrrolidone unit is a divalent group derived from N-vinylpyrrolidone.

  In the color filter copolymer of the present invention, the content ratio of the acrylate unit, the acrylate unit and the N-vinylpyrrolidone unit is not particularly limited, but preferably 3 to 30% by weight of the acrylate unit and N-vinyl. It contains 20 to 80% by weight of pyrrolidone units, and the balance is acrylic acid units, more preferably 5 to 25% by weight of acrylate units and 30 to 60% by weight of N-vinylpyrrolidone units, with the balance being acrylic acid units. It is.

  When the content of the acrylate unit is less than 3% by weight, the dispersibility of the pigment tends to be lowered. When the content ratio of the acrylate unit exceeds 30% by weight, the dissolution time with respect to alkali becomes longer, and the developability of the resist composition tends to be lowered. On the other hand, when the N-vinylpyrrolidone unit is less than 20% by weight, the dissolution time with respect to alkali becomes long and the developability of the resist composition tends to be lowered. When the content ratio of the N-vinylpyrrolidone unit exceeds 80% by weight, the dispersibility of the pigment tends to be lowered.

  The copolymer for a color filter of the present invention preferably has a weight average molecular weight (Mw) of 5000 to 20000, more preferably 9000 to 16000. If the polymerization average molecular weight is less than 5,000, the storage stability of the pigment dispersion tends to decrease. When the weight average molecular weight exceeds 20000, the viscosity of the pigment dispersion increases, and the coatability of the resist composition tends to decrease.

  The color filter copolymer of the present invention has an acid value of 30 to 200 mgKOH / g, preferably 90 to 160 mgKOH / g. When the acid value is less than 30 mgKOH / g, the dissolution time with respect to alkali becomes long, and the developability of the resist composition tends to be lowered. When the acid value exceeds 200 mgKOH / g, the viscosity of the pigment dispersion increases, and the coatability of the resist composition tends to decrease.

  The color filter copolymer of the present invention can be synthesized, for example, using a living radical polymerization method. More specifically, for example, an acrylic acid ester and acrylic acid are polymerized in the presence of a living radical polymerization initiator to synthesize a polymer block (X), and then N-vinylpyrrolidone or N-vinylpyrrolidone The color filter copolymer of the present invention can be obtained by a method of polymerizing acrylic acid and adding the polymer block (Y) to the polymer block (X). In the presence of a living radical polymerization initiator, N-vinylpyrrolidone or N-vinylpyrrolidone and acrylic acid are polymerized to synthesize a polymer block (Y), and then acrylic acid ester and acrylic acid are polymerized. The color filter copolymer of the present invention can also be obtained by the method of adding the polymer block (X) to the combined block (Y). In the production of the color filter copolymer of the present invention, an azo polymerization initiator may be used in combination for the purpose of accelerating the polymerization rate. Such a polymerization method is described, for example, in JP-A-2009-270105.

  As the living radical polymerization initiator, for example, an organic tellurium compound can be used. Specific examples of the organic tellurium compound include (methylterranylmethyl) benzene, (methylterranylmethyl) naphthalene, ethyl-2-methyl-2-methylterranyl-propionate, and ethyl-2-methyl-2-n-butylterranyl-propionate. Further, all of the organic tellurium compounds described in International Publication No. 2004/14848 and International Publication No. 2004/14962 can be exemplified. A living radical polymerization initiator can be used individually by 1 type or in combination of 2 or more types.

  Examples of the azo polymerization initiator include 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethyl). Valeronitrile), 1,1′-azobis (1-cyclohexanecarbonitrile), dimethyl-2,2′-azobisisobutyrate, 4,4′-azobis (4-cyanovaleric acid), 1,1′- Azobis (1-acetoxy-1-phenylethane), 2,2′-azobis (2-methylbutyramide), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2 ′ -Azobis (2-methylamidinopropane) dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2-methyl-N- (2- Hide Xylethyl) propionamide], 2,2′-azobis (2,4,4-trimethylpentane), 2-cyano-2-propylazoformamide, 2,2′-azobis (N-butyl-2-methylpropionamide) 2,2′-azobis (N-cyclohexyl-2-methylpropionamide) and the like. An azo polymerization initiator can be used individually by 1 type or in combination of 2 or more types.

  The amount of monomer compound used (total amount of acrylic ester, N-vinylpyrrolidone and acrylic acid) may be appropriately selected according to the molecular weight and molecular weight distribution of the finally obtained copolymer, It is 20-4000 mol with respect to 1 mol of living radical polymerization initiators, More preferably, it is 40-1500 mol.

  When the living radical polymerization initiator and the azo polymerization initiator are used in combination, the usage ratio of the azo polymerization initiator is usually 0.01 to 100 mol, preferably 1 mol to 1 mol of the living radical polymerization initiator. It is good to set it as 0.1-10 mol, More preferably, it is 0.1-5 mol.

  The polymerization reaction is carried out at a temperature of 0 to 150 ° C., preferably 20 to 100 ° C., more preferably 20 to 80 ° C. with or without stirring in a solvent or in a solvent, for 1 minute to 100 hours, preferably The reaction is completed in 0.1 to 30 hours, more preferably 0.1 to 15 hours. As the solvent, a solvent inert to the polymerization reaction can be used. For example, benzene, toluene, N, N-dimethylformamide, dimethyl sulfoxide, acetone, 2-butanone (methyl ethyl ketone), dioxane, hexafluoroisopropol, chloroform, Organic solvents such as carbon tetrachloride, tetrahydrofuran, ethyl acetate, trifluoromethylbenzene, propylene glycol monomethyl ether, water, methanol, ethanol, isopropanol, n-butanol, ethyl cellosolve, butyl cellosolve, 1-methoxy-2-propanol, diacetone Examples include aqueous solvents such as alcohol.

  After the completion of the polymerization reaction, the desired copolymer for color filter of the present invention can be separated from the resulting reaction mixture by an ordinary separation and purification means.

[Pigment dispersion]
The pigment dispersion of the present invention contains a pigment, a pigment dispersant, the color filter copolymer of the present invention and a solvent, and the pigment has a coating layer containing the color filter copolymer on at least a part of its surface. It is characterized by having. The pigment dispersion of the present invention can be used not only as a raw material for a resist composition but also as various inks and ink raw materials.

  Examples of the pigment include, but are not limited to, azo pigments, phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, indigo pigments, dioxazine pigments, perylene pigments, perinone pigments, isoindolinone pigments, and isoindoline. And condensed polycyclic pigments such as pigments, metal complex pigments, quinophthalone pigments, and diketopyrrolopyrrole pigments. A pigment can be used individually by 1 type or can be used in combination of 2 or more type.

  More specifically, for example, C.I. I. Pigment red 254, C.I. I. Pigment red 177, C.I. I. Pigment orange 36, C.I. I. Pigment green 58, C.I. I. Pigment green 36, C.I. I. Pigment green 7, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 139, C.I. I. Pigment yellow 138, C.I. I. Pigment blue 15: 6, C.I. I. Pigment violet 23, C.I. I. Pigment orange 38, C.I. I. Pigment orange 43, C.I. I. And CI Pigment Orange 71.

  The effect of the color filter copolymer of the present invention is further improved by using the pigment finely. The finer treatment of the pigment is performed, for example, by kneading the pigment and pulverized sodium sulfate in the presence or absence of a solvent. The pulverized mirabilite is anhydrous sodium sulfate having an average particle size of 5.5 μm or less and a content of particles having a particle size of 10.0 μm or more of 5% by volume or less. As a more specific pulverization method, the pigment and pulverized mirabilite are stirred and mixed with a mixer, the obtained mixture is dispersed in deionized water, the resulting fine pigment paste is dried, and the resulting dried product is obtained. The method of crushing is mentioned.

  By the pulverization method as described above, it is desirable to obtain a finer pigment having a volume average particle diameter of preferably 10 to 100 nm, more preferably 20 to 50 nm. When the volume average particle diameter of the pigment is less than 10 nm, the pigment is too cohesive and there is a tendency that a pigment dispersion in which the pigment is uniformly dispersed cannot be obtained. On the other hand, when the volume average particle diameter of the pigment exceeds 100 nm, the storage stability of the pigment dispersion is lowered and the pigment tends to aggregate. The volume average particle diameter of the pigment can be adjusted by appropriately selecting the amount of pulverized mirabilite used, the kneading time of the pigment and pulverized mirabilite, the pulverization time of the dried product, and the like.

  In the present specification, the volume average particle diameter of the pigment was determined in a beaker filled with ISOTON2 (trade name, electrolyte for measurement, manufactured by Beckman Coulter) using Multisizer 3 (trade name, manufactured by Beckman Coulter). In addition, the sample pigment can be dropped with a dropper while gently stirring, and the multimeter densitometer reading is adjusted to around 10%, and then measured using a 400 μm aperture.

  As described above, the pigment used in the present invention has a coating layer containing the color filter copolymer of the present invention on its surface. Here, the use ratio of the pigment and the color filter copolymer is not particularly limited, but the color filter copolymer is preferably 1 to 30 parts by weight, more preferably 5 to 20 parts per 100 parts by weight of the pigment. It is better to use parts by weight. If the amount of the color filter copolymer used is less than 1 part by weight, the effect of increasing the contrast of the image tends to be insufficient. On the other hand, when the usage-amount of the copolymer for color filters exceeds 30 weight part, there exists a tendency for the dispersibility of a pigment to fall. Moreover, the dissolution time with respect to alkali becomes long, and the developability of the resist composition tends to decrease.

  The content of the pigment (the pigment having the color filter copolymer deposited on the surface) in the pigment dispersion is not particularly limited, but is preferably 5 to 25% by weight of the total solid content of the pigment dispersion, more preferably 10 to 25% by weight. Thus, when the pigment content is sufficiently high, the amount of solvent volatilization during the formation of the coating film can be reduced, so that the burden on the environment can be reduced.

  The pigment dispersant is not particularly limited, and examples thereof include a resin-type dispersant and a surfactant-type dispersant. Among these, a resin-type dispersant is preferable from the viewpoint of sufficiently exerting the effect of the color filter copolymer. Examples of the resin-type dispersant include an oil-based resin-type dispersant and an aqueous resin-type dispersant.

  Examples of the oil-based resin dispersant include polyurethane, polyester, unsaturated polyamide, phosphate ester, polycarboxylic acid and its amine salt, ammonium salt, alkylamine salt, polycarboxylic acid ester, hydroxyl group-containing polycarboxylic acid ester, and polysiloxane. And modified polyacrylates.

  Examples of the aqueous resin dispersant include water-soluble polymer compounds such as alginic acids, polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, polyvinyl pyrrolidone, and gum arabic; styrene-acrylic acid resin, styrene-methacrylic acid Acid resin, styrene-acrylic acid-acrylic acid ester resin, styrene-maleic acid resin, styrene-maleic acid ester resin, methacrylic acid-methacrylic acid ester resin, acrylic acid-acrylic acid ester resin, isobutylene-maleic acid resin, vinyl- Examples include ethylenic double bond-containing resins such as ester resins and rosin-modified maleic resins; amine resins such as polyallylamine, polyvinylamine, and polyethyleneimine.

Various resin-type dispersants are commercially available. Specific examples of commercially available products include “Solsperse” 3000, 9000, 13240, 17000, 20000, 24000, 26000, 28000, 32000, 32500, 41000 (any Product name, manufactured by Nippon Lubrizol Co., Ltd.), “Disperbyk-” 108, 110, 112, 140, 142, 145, 161, 162, 163, 164, 166, 167, 182, 2000, 2001, 2050, 2070 2150, “BYK LPN-” 6919, 21116 (both trade names, manufactured by Big Chemie Japan), “EFKA-” 4401, 4403, 4406, 4010, 4015, 4046, 4047, 4050, 4055, 4060, 4080, 5064, 5207, 5244 (both trade names, manufactured by EFKA Additive), “Ajisper” PB821 (F), PB822, PB880 (both trade names, manufactured by Ajinomoto Fine Techno Co., Ltd.), Hinoact T-8000 (trade name, Kawa Kenkyu Fine Chemical Co., Ltd.), Disparon PW-36, “Disvalon DA-” 325, 375, 7301 (all trade names, manufactured by Enomoto Kasei Co., Ltd.), and the like.
The resin type dispersant preferably has a weight average molecular weight of about 1000 to 30000.

Surfactant type dispersants include naphthalene sulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate, anionic activator such as polyoxyethylene alkyl phosphate ester, nonionic activator such as polyoxyethylene alkyl ether, alkylamine And cationic active agents such as salts and quaternary ammonium salts. Various surfactant type dispersants are commercially available, and specific examples thereof include, for example, “Demol” N, RN, MS, SN-B, “Emulgen” 120, 430, “Acetamine” 24, 86. Coatamine 24P (all trade names, manufactured by Kao Corporation), “Plisurf” AL, A208F (all trade names, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), “Arcade” C-50, T-28, T-50 (both are trade names, manufactured by Lion Corporation) and the like.
A pigment dispersant can be used individually by 1 type, or can be used in combination of 2 or more type.

  The content of the pigment dispersant in the pigment dispersion is not particularly limited, but is preferably 10 to 60 parts by weight, more preferably 20 to 50 parts by weight with respect to 100 parts by weight of the pigment. When the content of the pigment dispersant is less than 10 parts by weight, the effect of the pigment dispersant tends to be insufficient. On the other hand, when the content of the pigment dispersant exceeds 60 parts by weight, the viscosity of the pigment dispersion tends to be increased and handling (handleability) tends to be deteriorated.

  The solvent is not particularly limited, and any of an aqueous solvent and a non-aqueous solvent may be used. Examples of the aqueous solvent generally include a compound having a highly hydrophilic functional group such as a hydroxy group, a compound having a polyglycol skeleton, and the like. Examples of the non-aqueous solvent include ester solvents, ether solvents, ketone solvents, and the like. Specific examples of the solvent include methoxypropyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, butyl cellosolve, water and the like. A solvent can be used individually by 1 type or in combination of 2 or more types.

  The pigment dispersion of the present invention may contain conventionally known additives for pigment dispersion, if necessary. Examples of such additives include pH adjusters, antioxidants, ultraviolet absorbers, preservatives, and fungicides.

The pigment dispersion of the present invention can be obtained, for example, by a production method including steps (1) to (3).
Step (1): The pigment and the color filter copolymer of the present invention are kneaded.
Step (2): The kneaded product obtained in Step (1) is dried and / or pulverized to obtain a pigment having a coating layer containing a color filter copolymer on the surface.
Step (3): The pigment having the coating layer obtained in step (2) on the surface, a pigment dispersant and a solvent are mixed to obtain a pigment dispersion.

  Thus, before mixing the pigment, the pigment dispersant and the solvent in the step (3), the pigment and the color filter copolymer are kneaded in the steps (1) and (2) to form the pigment surface. An embodiment in which a coating layer containing a color filter copolymer is formed is preferred. According to this embodiment, the effect of increasing the contrast of the image by the color filter copolymer and the effect of improving the developability of the resist composition are sufficiently exhibited without impairing the dispersibility of the pigment in the pigment dispersion.

  In addition, the pigment dispersion obtained by the production method of the present invention sufficiently suppresses aggregation and precipitation of pigments, has excellent storage stability, and suppresses the increase in viscosity over time to a low level. Moreover, the resist composition containing this pigment dispersion can shorten the removal time with an alkali and improve developability in the development process in photolithography in producing a color filter. Furthermore, the contrast of the image projected on the color liquid crystal panel can be enhanced by using a color filter formed from a resist composition containing this pigment dispersion.

More specifically, the steps (1) to (3) are performed as follows.
In the step (1), the pigment and the color filter copolymer are kneaded, for example, by adding a predetermined amount of the pigment and the color filter copolymer to diethylene glycol (DEG), ethylene glycol, polyethylene glycol or the like as necessary. It is carried out by kneading using a general kneader capable of applying a shearing force in the presence of a water-soluble organic solvent. The kneading temperature and the kneading time are not particularly limited, and are appropriately selected according to the type and amount of the pigment and color filter copolymer, and are, for example, about 25 to 150 ° C. and about 1 to 15 hours. .

  In the step (1), the pigment and the color filter copolymer can be kneaded and the pigment can be miniaturized at the same time. Examples of the method include a method of kneading pulverized sodium sulfate together with a pigment and a color filter copolymer. Here, the amount of pulverized mirabilite used is not particularly limited, and is appropriately selected according to the type and amount of pigment used, but is preferably 5 to 30 parts by weight, more preferably 8 parts per 100 parts by weight of pigment. ~ 15 parts by weight.

  In the step (2), the kneaded product obtained in the step (1) is dried and / or pulverized. In a preferred embodiment, the kneaded product obtained in the step (1) is dried, and the obtained dried product is pulverized. Drying of the kneaded product is performed at a temperature of about 80 to 130 ° C. and is completed in about 6 to 20 hours. The dry product is pulverized using a general powder pulverizer such as a bantam mill or a hammer mill. Thereby, the pigment which has the coating layer containing the copolymer for color filters on the surface can be obtained. At this stage, a known pigment derivative (dispersing aid) may be mixed with the pigment having the coating layer obtained on the surface.

  In the step (1), when pulverized sodium sulfate is used together with the pigment and the color filter copolymer, and kneading and refining of the pigment are simultaneously performed, the obtained kneaded material is dispersed in water to form an aqueous slurry. It is preferable to dry and grind the aqueous slurry obtained. At this time, the solid content weight of the aqueous slurry is preferably about 1 to 6% by weight from the viewpoint of workability and the like.

  A preferred embodiment for drying and pulverizing the aqueous slurry includes a form in which a solid is separated from the aqueous slurry, and the separated solid is dried and / or pulverized. More preferably, the solid is dried and ground. The conditions for drying and pulverizing the aqueous slurry and its solid are the same as those for drying and pulverizing the kneaded product of the pigment and the color filter copolymer. Thereby, the refined | miniaturized pigment which has a coating layer containing the copolymer for color filters of this invention is obtained.

  In step (3), the pigment having the coating layer obtained in step (2) on the surface, a pigment dispersant, and a solvent are mixed to obtain a pigment dispersion. The pigment dispersion of the present invention includes, for example, a pigment having a coating layer obtained in step (2) (which may contain a pigment derivative as a dispersion aid), a pigment dispersant, a solvent, and an additive as necessary. Can be obtained by dispersing with a known dispersing machine such as a bead mill or a sand mill. In the pigment dispersion of the present invention, the solid content concentration of the pigment, the pigment dispersant, and the dispersion aid is set to the total amount of the pigment dispersion from the viewpoint of pigment dispersibility, retention of pigment dispersibility, and suppression of viscosity increase. It is preferable to adjust to the range of 15 to 30% by weight.

  When a copolymer having an acrylic ester unit, an acrylic acid unit, an N-vinylpyrrolidone unit and a styrene unit is used as the color filter copolymer, the pigment and the copolymer are prepared in the same manner as described above. The pigment dispersion of the present invention can be prepared after kneading. Further, the pigment dispersion of the present invention using an organic solvent as a dispersion medium can be directly prepared by mixing the copolymer with a pigment having no coating layer on the surface, a pigment dispersant and an organic solvent. Among copolymer for color filter containing styrene unit, polymer block (Xa) containing acrylate unit, styrene unit and acrylic acid unit, polymer block containing N-vinylpyrrolidone unit and acrylic acid unit A copolymer consisting of (Y) is preferred.

[Resist composition]
The resist composition of the present invention contains the above pigment dispersion and a photosensitive compound. The photosensitive compound is an organic compound used for photolithography. As the photosensitive compound, any photosensitive compound that can be used in the photolithography method can be used, but preferred forms of the photosensitive compound include a photosensitive resin, a photopolymerization initiator, a photopolymerizable monomer, and / or a photopolymerizable compound. Prepolymers (dimers, trimers and oligomers) may be included.

  As the pigment dispersion, the above-described pigment dispersion of the present invention is used. The content of the pigment dispersion in the resist composition is not particularly limited, but from the viewpoint of developability of the color filter finally obtained, the weight ratio of the pigment to the total solid content of the resist composition is 5 to 70% by weight. Preferably, it is more preferably 15 to 60% by weight. When the weight ratio of the pigment is less than 5% by weight, it tends to be difficult to produce a color filter that can contribute to display of an image having desired brightness, brightness, and contrast. When the weight ratio of the pigment exceeds 70% by weight, the pigment dispersibility is lowered and the viscosity of the resist composition is increased, and the coating property and the color filter characteristics at the time of producing the color filter tend to be lowered.

  The photosensitive resin is not particularly limited as long as it is a resin that can be used in the photolithography method. For example, an ethylene-vinyl acetate copolymer, an ethylene-vinyl chloride copolymer, an ethylene vinyl copolymer, polystyrene, acrylonitrile- Styrene copolymer, ABS resin, polymethacrylic acid resin, ethylene methacrylic acid resin, polyvinyl chloride, chlorinated vinyl chloride, polyvinyl alcohol, cellulose acetate propionate, cellulose acetate butyrate, polyamide (polyamide 6, polyamide 66, polyamide) 12), polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyvinyl acetal, polyether ether ketone, polyether sulfone, polyphenylene sulfide, polyarylate, polybi Butyral, epoxy resin, phenoxy resin, polyimide, polyamideimide, polyetherimide, phenolic resin, urea resin and the like.

  As the photosensitive resin, a copolymer of a monomer containing an ethylenically unsaturated double bond (hereinafter referred to as “ethylene monomer”) and a carboxylic acid monomer can be used. Examples of the ethylene monomer include alkyl (meth) acrylate, benzyl (meth) acrylate, glycidyl (meth) acrylate, styrene, α-methylstyrene, N-vinyl-2-pyrrolidone, and the like. In the alkyl (meth) acrylate, the alkyl moiety is methyl, ethyl, n-propyl, isopropyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, 2-ethylhexyl, n-octyl, n-decyl. And a linear or branched alkyl group having 1 to 10 carbon atoms such as 2-hydroxyethyl. An ethylene-type monomer can be used individually by 1 type or in combination of 2 or more types. Examples of the carboxylic acid monomer include acrylic acid, methacrylic acid, dimer of acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, and acid anhydrides thereof. Carboxylic acid monomers can be used alone or in combination of two or more.

  In the present invention, a commercially available resin can be used as the photosensitive resin. Examples of commercially available resins include acrylic resins (“Aronix M-” 5600, 6200, 7100, 9050, all of which are trade names, manufactured by Toagosei Co., Ltd.).

  The content of the photosensitive resin in the resist composition is not particularly limited, but when adding the photosensitive resin to the resist composition, it is preferably 10 to 60% by weight of the total solid content of the resist composition, more preferably 15 to 50% by weight. If the content of the photosensitive resin is less than 10% by weight, the film strength of the pattern formed on the glass substrate becomes insufficient, and the long-term durability tends to be lowered, while the content of the photosensitive resin is low. If it exceeds 60% by weight, the dispersibility of the pigment becomes insufficient even in the resist composition, and it tends to be difficult to form a pattern having desired characteristics when producing a color filter.

  The photopolymerization initiator is not particularly limited as long as it generates free radicals upon irradiation with energy such as ultraviolet rays. For example, benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, 4,4′bis (dimethyl) Amino) benzophenone, 4,4′bis (diethylamino) benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-benzoyl-4′-methyldiphenyl sulfide, benzylmethyl ketal, dimethylaminomethylbenzoate, 2-n-butoxyethyl- 4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3′-dimethyl-4-methoxybenzophenone, methylobenzoyl formate, 2-methyl-1- (4- (methylthio) pheny ) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 1- (4-dodecylphenyl) -2hydroxy-2-methyl Propan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxythioxanthone and the like.

In the present invention, a commercially available photopolymerization initiator can be used. For example, “Irgacure” 184, 369, 651, 907 (all trade names, manufactured by Ciba Specialty Chemicals), Darocur (trade names, Merck) Co., Ltd.), Adeka 1717 (trade name, manufactured by ADEKA Corporation) and other ketone compounds, 2,2′-bis (o-chlorophenyl) -4,5,4′-tetraphenyl-1,2′-bi Examples include biimidazole compounds such as imidazole (manufactured by Kurokin Kasei Co., Ltd.).
A photoinitiator can be used individually by 1 type or in combination of 2 or more types.

  The content of the photopolymerization initiator in the resist composition is not particularly limited, but is preferably 0.05 to 10% by weight, more preferably 0.5 to 5% by weight, based on the total solid content of the resist composition. . When the content of the photopolymerization initiator is less than 0.05% by weight, the photocurability of the resist composition becomes insufficient, and the workability in the process of forming a color filter by a photolithography method tends to be lowered. In addition, the developability and sensitivity of the color filter tend to decrease. When the content of the photopolymerization initiator exceeds 10% by weight, aggregates and precipitates are formed in the resist composition during the storage of the resist composition, and the developability of the color filter formed using this and Sensitivity tends to decrease.

  Examples of the photopolymerizable monomer include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters thereof, and amides. Specific examples of the photopolymerizable monomer include, for example, methyl (meth) acrylate, hydroxyethyl (meth) acrylate, alkyl acrylates of benzyl (meth) acrylate; (meth) acrylamide, N-hexyl (meth) acrylamide, vinyl ( (Meth) acrylamides such as (meth) acrylamide and allyl (meth) acrylamide; vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether and butyl vinyl ether; vinyl esters such as vinyl acetate, vinyl butyrate and vinyl benzoate Styrenes such as styrene, methylstyrene and p-acetoxystyrene; vinyl ketones such as alkyl vinyl ketone and phenyl vinyl ketone; ethylene, propylene, isobutylene, butadiene, isoprene, etc. Olefins; maleimide, N- acryloyl acrylamide, N- acetyl methacrylamide, N- propionyl unsaturated imides such as methacrylamide; N- vinylpyrrolidone, acrylonitrile, methacrylonitrile, and the like. A photopolymerizable monomer can be used individually by 1 type or in combination of 2 or more types. Among these photopolymerization initiators, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohol compounds and amides of unsaturated carboxylic acids and aliphatic polyvalent amine compounds are preferred.

  Examples of the photopolymerizable prepolymer include (a) an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent and a monofunctional or polyfunctional isocyanate or epoxy, (b) ) Dehydration condensation reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent and a monofunctional or polyfunctional carboxylic acid, (c) an unsaturated carboxylic acid ester having an electrophilic substituent Or an amide and an addition reaction product of a monofunctional or polyfunctional alcohol, amine or thiol, (d) an unsaturated carboxylic acid ester or amide having a leaving substituent, and a monofunctional or polyfunctional Examples include substitution reaction products with functional alcohols, amines or thiols. In the above (a) to (d), a compound group in which the unsaturated carboxylic acid ester is replaced with unsaturated phosphonic acid, styrene, vinyl ether or the like can also be used as the photopolymerizable prepolymer. In the above (a) to (d), examples of the nucleophilic substituent include a hydroxy group, an amino group, and a mercapto group, and examples of the electrophilic substituent include an isocyanate group and an epoxy group. Examples of the leaving substituent include a halogen atom and a tosyloxy group.

  The content of the photopolymerizable monomer and / or photopolymerizable prepolymer in the resist composition is not particularly limited, but preferably 5% of the total solid content of the resist composition from the viewpoint of developability and sensitivity of the obtained color filter. It is -70 weight%, More preferably, it is 10-60 weight%. In many cases, these compounds are used, for example, to improve the adhesion between a film formed from a resist composition and a glass substrate, but have a structure that matches the purpose for other purposes. You may select suitably and use.

  As the solvent, a solvent for a resist composition can be used without particular limitation, for example, alcohols such as methanol, ethanol, n-propanol, isopropanol, ethylene glycol, propylene glycol; terpenes such as α- or β-terpineol, etc. Ketones such as acetone, methyl ethyl ketone, cyclohexanone and N-methyl-2-pyrrolidone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolve, methyl cellosolve, ethyl cellosolve, carbitol, methylcarbitol, ethyl Carbitol, butyl carbitol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, Glycol ethers such as reethylene glycol monomethyl ether and triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl And acetates such as ether acetate, propylene glycol monoethyl ether acetate, and 3-methoxybutyl acetate; In the present invention, various commercially available solvents can be used, and examples thereof include propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether (both manufactured by Daicel Chemical Industries, Ltd.). A solvent can be used individually by 1 type or in combination of 2 or more types.

  Although the content of the solvent in the resist composition is not particularly limited, the pigment dispersibility in the resist composition, the coating property of the resist composition, the brightness of the image displayed on the color liquid crystal display including the color filter finally obtained, Considering brightness, contrast and the like, the amount is preferably 100 to 900 parts by weight, more preferably 200 to 500 parts by weight with respect to 100 parts by weight of the total solid content of the resist composition. When the content of the solvent is less than 100 parts by weight, the viscosity of the resist composition increases, and the pigment dispersibility and coating property tend to decrease. When the content of the solvent exceeds 900 parts by weight, it tends to be difficult to produce a color filter that can contribute to display an image having desired brightness, luminance, and contrast.

  The resist composition of the present invention may contain various additives for the resist composition as necessary. Examples of such additives include sensitizers, chain transfer agents, fluorinated organic compounds, thermal polymerization initiators, thermal polymerization components, thermal polymerization inhibitors, fillers, surfactants, adhesion promoters, and antioxidants. Agents, ultraviolet absorbers, anti-aggregation agents and the like. An additive can be used individually by 1 type or in combination of 2 or more types.

  The resist composition of the present invention includes a solvent, a pigment dispersion, a photosensitive compound (for example, at least one selected from a photosensitive resin, a photopolymerization initiator, a photopolymerizable monomer, and / or a prepolymer), and other components as necessary. The liquid mixture obtained by adding the additive can be obtained by shaking using a paint conditioner or the like.

  By using the resist composition of the present invention and utilizing a photolithography method, a predetermined pattern can be formed on the surface of a predetermined glass substrate to produce a color filter.

  Hereinafter, the present invention will be specifically described with reference to synthesis examples, examples and comparative examples. In the following, “parts” and “%” are based on weight unless otherwise specified. Moreover, the polymerization rate, weight average molecular weight (Mw), molecular weight distribution (PDI), and acid value of the copolymer shown in the synthesis examples were evaluated according to the following methods.

[Polymerization rate]
Using a nuclear magnetic resonance apparatus (trade name: AVANCE500, manufactured by Bruker BioSpin Co., Ltd.), the ¹ H-NMR spectrum is measured, and the polymerization rate is calculated from the peak area ratio between the vinyl group of the monomer and the polymer side chain. did.

[Weight average molecular weight (Mw) and molecular weight distribution (PDI)]
An HPLC (trade name: HPLC 1100 series, manufactured by Agilent Technologies) equipped with a gel permeation column (trade name: GPC KF-806L, manufactured by Showa Denko KK), and N—10 mM lithium bromide in the mobile phase. A calibration curve was prepared using a methylpyrrolidone solution and polystyrene (molecular weight 427,000, 190,000, 96,400, 37,400, 10,200, 2,630, 440, 92) as a standard substance, The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured, and the molecular weight distribution (PDI = Mw / Mn) was calculated.

[Acid value]
The acid value represents the weight of potassium hydroxide required to neutralize the acidic component per gram of solid content. A measurement sample was dissolved in tetrahydrofuran, and a potentiometric titrator (trade name: GT-06, Mitsubishi) The resulting solution was subjected to neutralization titration with an ethanol solution of 0.5M potassium hydroxide. The acid value was calculated by the following equation using the inflection point of the titration pH curve as the titration end point.
A = 56.11 × Vs × 0.5 × f / w
[In formula, A shows an acid value (mgKOH / g). Vs indicates the amount (ml) of 0.5M potassium hydroxide ethanol solution required for the sample titration. f represents the titer of an ethanol solution of 0.5M potassium hydroxide. w represents the product sample amount (sample weight × nonvolatile content, g). ]

The main monomer components, solvents and reagents used in the following synthesis examples and examples are as follows.
[Monomer component]
Isobornyl acrylate: Reagent manufactured by Tokyo Chemical Industry Co., Ltd. Acrylic acid: Reagent manufactured by Tokyo Chemical Industry Co., Ltd. N-Vinylpyrrolidone: Reagent manufactured by Wako Pure Chemical Industries, Ltd. Styrene: Reagent manufactured by Wako Pure Chemical Industries, Ltd.

[solvent]
Propylene glycol monomethyl ether acetate: Trade name; Arcosolve PMA, manufactured by Kyowa Hakko Chemical Co., Ltd., hereinafter referred to as “PMA”.
Propylene glycol monomethyl ether: Trade name; Arcosolv PM, manufactured by Kyowa Hakko Chemical Co., Ltd., hereinafter referred to as “PM”)
Dimethyl sulfoxide: manufactured by Kanto Chemical Co., Inc., hereinafter referred to as “DMSO”.

[reagent]
Metal tellurium: trade name: Tellurium (-40 mesh), manufactured by Aldrich n-butyllithium: manufactured by Aldrich, 1.6 M hexane solution Azobisisobutyronitrile: polymerization initiator, trade name: AIBN, manufactured by Otsuka Chemical Co., Ltd. Hereinafter, it is referred to as “AIBN”.

<Synthesis of polymerization initiator>
(Synthesis Example 1) Synthesis of ethyl-2-methyl-2-n-butylteranyl-propionate (hereinafter referred to as “BTEE”) 6.38 g (50 mmol) of metal tellurium was suspended in 50 ml of tetrahydrofuran, and n-butyllithium 34 was added thereto. 4 ml (55 mmol) was slowly added dropwise at room temperature over 10 minutes. The resulting reaction solution was stirred for 20 minutes until the metal tellurium completely disappeared, and then 10.7 g (55 mmol) of ethyl-2-bromo-isobutyrate was added at room temperature and stirred for 2 hours. After completion of the reaction, the solvent was concentrated under reduced pressure, followed by distillation under reduced pressure to obtain 8.98 g (yield 59.5%) of BTEE as a yellow oil. BTEE is used as a living radical polymerization initiator in Synthesis Examples 2 to 8 described later.

<Synthesis of copolymer>
(Synthesis Example 2)
Into a flask equipped with an argon gas introduction tube and a stirrer, 872.0 g of isobornyl acrylate, 128.0 g of acrylic acid, 4.38 g of AIBN, and 667.0 g of PM were charged. After purging with argon, BTEE (40.0 g) was added. And reacted at 60 ° C. for 22 hours. The polymer contained in the obtained reaction solution had a polymerization rate of 99%, a weight average molecular weight (Mw) of 4,530, and a molecular weight distribution (PDI) of 1.22.

  Furthermore, a mixed solution of 872.0 g of N-vinylpyrrolidone previously substituted with argon, 128.0 g of acrylic acid, 6.57 g of AIBN and 1222.0 g of PM was added to the above reaction solution, and reacted at 60 ° C. for 26 hours. The polymerization rate of the polymer contained in the obtained reaction mixture was 98%. 6467.0 g of PM was added to the reaction mixture, and the resulting mixture was poured into 67.0 L of n-heptane under stirring. The precipitated polymer was suction filtered, dried and dissolved in DMSO to obtain a copolymer solution (5670 g) having a solid content of 30%. The weight average molecular weight (Mw) was 13,000, the molecular weight distribution (PDI) was 1.27, and the acid value was 103 mgKOH / g.

(Synthesis Example 3)
A flask equipped with an argon gas inlet tube and a stirrer was charged with 93.6 g of isobornyl acrylate, 6.4 g of acrylic acid, 0.438 g of AIBN and 66.7 g of PM, and after substitution with argon, BTEE (4.0 g) was added. And reacted at 60 ° C. for 22 hours. The polymer contained in the obtained reaction solution had a polymerization rate of 99%, a weight average molecular weight (Mw) of 3,900, and a molecular weight distribution (PDI) of 1.28.

  Further, a mixed solution of 93.6 g of N-vinylpyrrolidone previously substituted with argon, 6.4 g of acrylic acid, 0.876 g of AIBN and 122.2 g of PM was added to the above reaction solution, and reacted at 60 ° C. for 26 hours. The polymerization rate of the polymer contained in the obtained reaction mixture was 96%. To this reaction mixture was added 647.0 g PM and the resulting mixture was poured into n-heptane (6.7 L) under stirring. The precipitated polymer was suction filtered, dried and dissolved in DMSO to obtain a copolymer solution (331 g) having a solid content of 30%. The weight average molecular weight (Mw) was 12,600, the molecular weight distribution (PDI) was 1.25, and the acid value was 33 mgKOH / g.

(Synthesis Example 4)
A flask equipped with an argon gas inlet tube and a stirrer was charged with 122.0 g of isobornyl acrylate, 18.0 g of acrylic acid, 0.438 g of AIBN, and 103.5 g of PM, and after substitution with argon, BTEE (4.0 g) was added. , Reacted at 60 ° C. for 16 hours. The polymer contained in the obtained reaction solution had a polymerization rate of 99%, a weight average molecular weight (Mw) of 6,850, and a molecular weight distribution (PDI) of 1.35.

  Further, a mixed solution of 52.4 g of N-vinylpyrrolidone previously substituted with argon, 7.6 g of acrylic acid, 0.657 g of AIBN and 73.3 g of PM was added to the above reaction solution, and reacted at 60 ° C. for 26 hours. The polymerization rate of the polymer contained in the obtained reaction mixture was 98%. To this reaction mixture was added 647.0 g PM and the resulting mixture was poured into n-heptane (6.7 L) under stirring. The precipitated polymer was suction filtered, dried and dissolved in DMSO to obtain a copolymer solution (521 g) having a solid content of 30%. The weight average molecular weight (Mw) was 12,000, the molecular weight distribution (PDI) was 1.31, and the acid value was 103 mgKOH / g.

(Synthesis Example 5)
A flask equipped with an argon gas introduction tube and a stirrer was charged with 122.0 g of isobornyl acrylate, 25.6 g of acrylic acid, 0.438 g of AIBN and 98.4 g of PM. After purging with argon, BTEE (4.0 g) was added. , Reacted at 60 ° C. for 16 hours. The polymer contained in the obtained reaction solution had a polymerization rate of 99%, a weight average molecular weight (Mw) of 6,960, and a molecular weight distribution (PDI) of 1.47.

  Further, a mixed solution of 52.4 g of N-vinylpyrrolidone previously substituted with argon, 0.657 g of AIBN and 64.0 g of PM was added to the above reaction solution, and reacted at 60 ° C. for 22 hours. The polymerization rate of the polymer contained in the obtained reaction mixture was 99%. To this reaction mixture was added 647.0 g PM and the resulting mixture was poured into n-heptane (6.7 L) under stirring. The precipitated polymer was suction filtered, dried and dissolved in DMSO to obtain a copolymer solution (571 g) having a solid content of 30%. The weight average molecular weight (Mw) was 10,900, the molecular weight distribution (PDI) was 1.49, and the acid value was 102 mgKOH / g.

(Synthesis Example 6)
A flask equipped with an argon gas introduction tube and a stirrer was charged with 83.3 g of isobornyl acrylate, 16.7 g of acrylic acid, 0.438 g of AIBN, and 81.8 g of PM, and after substitution with argon, BTEE (4.0 g) was added. And reacted at 60 ° C. for 14 hours. The polymer contained in the obtained reaction solution had a polymerization rate of 96%, a weight average molecular weight (Mw) of 4,960, and a molecular weight distribution (PDI) of 1.25.

  Further, a mixed solution of 83.3 g of N-vinylpyrrolidone previously substituted with argon, 16.7 g of acrylic acid, 0.657 g of AIBN and 122.2 g of PM was added to the above reaction solution, and reacted at 60 ° C. for 23 hours. The polymerization rate of the polymer contained in the obtained reaction mixture was 98%. To this reaction mixture, 647.0 g of PM was added and the resulting mixture was poured into n-heptane (6.7 L) under stirring. The precipitated polymer was suction filtered, dried and dissolved in DMSO to obtain a copolymer solution (611 g) having a solid content of 30%. The weight average molecular weight (Mw) was 13,700, the molecular weight distribution (PDI) was 1.30, and the acid value was 132 mgKOH / g.

(Synthesis Example 7)
A flask equipped with an argon gas introduction tube and a stirrer was charged with 79.5 g of isobornyl acrylate, 20.5 g of acrylic acid, 0.438 g of AIBN and 81.8 g of PM, and after substitution with argon, BTEE (4.0 g) was added. And reacted at 60 ° C. for 14 hours. The polymer contained in the obtained reaction solution had a polymerization rate of 95%, a weight average molecular weight (Mw) of 5,360, and a molecular weight distribution (PDI) of 1.25.

  Further, a mixed solution of 79.5 g of N-vinylpyrrolidone previously substituted with argon, 20.5 g of acrylic acid, 0.657 g of AIBN and 122.2 g of PM was added to the reaction solution, and the mixture was reacted at 60 ° C. for 23 hours. The polymerization rate of the polymer contained in the obtained reaction mixture was 98%. To this reaction mixture, 647.0 g of PM was added and the resulting mixture was poured into n-heptane (6.7 L) under stirring. The precipitated polymer was suction filtered, dried and dissolved in DMSO to obtain a copolymer solution (581 g) having a solid content of 30%. The weight average molecular weight (Mw) was 13,900, the molecular weight distribution (PDI) was 1.34, and the acid value was 167 mgKOH / g.

(Synthesis Example 8)
A flask equipped with an argon gas introduction tube and a stirrer was charged with 60.0 g of isobornyl acrylate, 27.2 g of styrene, 12.8 g of acrylic acid, 0.657 g of AIBN and 66.7 g of PM, and after substitution with argon, BTEE (4 0.0 g) was added and reacted at 60 ° C. for 48 hours. The polymer contained in the obtained reaction solution had a polymerization rate of 95%, a weight average molecular weight (Mw) of 5,850, and a molecular weight distribution (PDI) of 1.36.

  Further, a mixed solution of 87.2 g of N-vinylpyrrolidone previously substituted with argon, 12.8 g of acrylic acid, 1.31 g of AIBN and 122.2 g of PM was added to the above reaction solution, and reacted at 60 ° C. for 62 hours. The polymerization rate of the polymer contained in the obtained reaction mixture was 90%. To this reaction mixture, 647.0 g of PM was added and the resulting mixture was poured into n-heptane (6.7 L) under stirring. The precipitated polymer was suction filtered, dried and dissolved in DMSO to obtain a copolymer solution (605 g) having a solid content of 30%. The weight average molecular weight (Mw) was 12,700, the molecular weight distribution (PDI) was 1.35, and the acid value was 110 mgKOH / g.

  The physical properties of the copolymers obtained in Synthesis Examples 2 to 8 are summarized in Table 1 below.

(Synthesis Example 9) Production of pulverized mirabilite Dry air was fed into a 0.65 MPa jet mill (trade name: Superjet mill, airflow pulverizer, manufactured by Nissin Engineering Co., Ltd.) And an average particle diameter of 20 μm, manufactured by Mitajiri Chemical Industry Co., Ltd.) were supplied at 45 kg / hr and continuously pulverized. The pulverized salt cake discharged from the pulverizer was collected in a lump with a bag filter. The obtained pulverized mirabilite had an average particle size of 3.6 μm and a content of particles having a particle size of 10 μm or more was 0.4% by volume. The average particle size and the content of particles having a particle size of 10 μm or more were obtained by adding powder frame mirabilite to isobutyl alcohol and dispersing with ultrasonic for 1 minute, and using a microtrack particle size distribution measuring device (trade name: MT-3300II, Nikkiso Co., Ltd. )) To obtain the particle size distribution.

(Synthesis Example 10) Preparation of Blue Fine Pigment Pigment 300 g of blue pigment (CI Pigment Blue 15: 6, trade name: Lionol Blue E, manufactured by Toyo Ink Manufacturing Co., Ltd.), 3000 g of pulverized salt cake obtained in Synthesis Example 9 , And diethylene glycol (manufactured by Nippon Shokubai Co., Ltd.) 850 g were charged into a double arm kneader (manufactured by Moriyama Co., Ltd., 5 L) and kneaded for 9 hours. To the obtained kneaded product, 150 g of the copolymer solution obtained in Synthesis Example 2 was added and further kneaded for 90 minutes. The obtained kneaded material was put into 8 L of warm water (70 ° C.) and stirred for 30 minutes to prepare a slurry liquid.

  The obtained slurry was filtered with a Buchner funnel to collect solids, and the obtained solids were washed with deionized water. Washing with deionized water was performed until the electrical conductivity of the water after washing was 3 μS / cm or less. The solid after washing was dried at 90 ° C. for 16 hours with a dryer and pulverized with a pulverizer (trade name: Sample Mill SK-M2, manufactured by Kyoritsu Riko Co., Ltd.). A blue micronized pigment with the coalescence deposited on the surface was obtained.

(Synthesis Examples 11 to 16) Preparation of Blue Refinement Pigment Synthesis Example except that the copolymer solutions obtained in Synthesis Examples 3 to 8 were used in place of the copolymer solution obtained in Synthesis Example 2, respectively. In the same manner as in Example 10, blue refined pigments of Synthesis Examples 11 to 16 in which the copolymers obtained in Synthesis Examples 3 to 8 were respectively deposited on the surfaces were obtained.

(Synthesis example 17) Preparation of yellow refinement | purification pigment It replaces with a blue pigment (CI Pigment Blue15: 6), and a yellow pigment (CI Pigment Yellow 138, brand name: Paliolto Yellow).
Except for using L0960HD (manufactured by BASF Japan Ltd.), in the same manner as in Synthesis Example 10, a yellow micronized pigment having the copolymer obtained in Synthesis Example 2 deposited on its surface was obtained.

(Comparative Synthesis Example 1) Preparation of Blue Refinement Pigment Instead of 150 g of the copolymer solution obtained in Synthesis Example 2, a resin-type dispersant (vinyl ester resin, trade name: Lipoxy SPC2000, solid content: 40% by weight, A blue refined pigment was obtained in the same manner as in Synthesis Example 10 except that 112.5 g (manufactured by Showa Denko KK) was used.

(Comparative Synthesis Example 2) Preparation of Blue Refined Pigment A blue refined pigment was obtained in the same manner as in Synthesis Example 10 except that 150 g of the copolymer solution obtained in Synthesis Example 2 was not used.

(Comparative Synthesis Example 3) Preparation of Yellow Refined Pigment Instead of 150 g of the copolymer solution obtained in Synthesis Example 2, a resin-type dispersant (vinyl ester resin, trade name: Lipoxy SPC2000, solid content 40 wt%, A yellow refined pigment was obtained in the same manner as in Synthesis Example 17 except that 112.5 g (manufactured by Showa Denko KK) was used.

(Comparative Synthesis Example 4) Preparation of Yellow Refined Pigment A yellow refined pigment was obtained in the same manner as in Synthesis Example 17 except that 150 g of the copolymer solution obtained in Synthesis Example 2 was not used.

Example 1 Preparation of Blue Pigment Dispersion Pigment Dispersant (trade name: BYK-LPN21116, manufactured by Big Chemie Japan Co., Ltd.) 33.75 g (98.2 parts by weight), Resin Type Pigment Dispersant (Vinyl Ester Resin) Trade name: Lipoxy SPC2000, solid content 40% by weight, Showa Denko KK) 15.34 g (44.6 parts by weight), PMA 62.21 g (181.0 parts by weight) and PM 21.00 g (61 .1 part by weight) was put into a mixer having an internal volume of 500 mL and stirred for 10 minutes with a disper to perform preliminary dispersion. The obtained preliminary dispersion is composed of 33.47 g of the blue micronized pigment obtained in Synthesis Example 10 and 0.9 g of a pigment derivative (pigment dispersing aid, trade name: Solsperse 12000, manufactured by Avicia Co., Ltd.). 34.37 g (100 parts by weight) of pigment was added, and the mixture was further stirred for 60 minutes to obtain a pigment dispersion.

  To the obtained pigment dispersion, 666 g of inorganic beads having an average particle diameter of 0.8 mm (made by zirconia, trade name: Toray ceramic pulverized ball, manufactured by Toray Industries, Inc.) and 33.33 g of PMA were added and stirred at room temperature for 30 minutes. Then, after carrying out the first stage dispersion operation, the inorganic beads were removed from the obtained mixed dispersion using a filter (trade name: PALL HDCII Membrane Filter, manufactured by PALL). Next, 600 g of inorganic beads having an average particle size of 0.1 mm (trade name: Toray ceram crushed ball, manufactured by Toray Industries, Inc.) and 75 g of PM were added to the obtained pigment dispersion, and the mixture was further stirred for 60 minutes. A second stage dispersion operation was performed.

  From the obtained mixed dispersion, inorganic beads were removed by filtration using a 2.5 μm mesh filter (trade name: PALL HDCII Membrane Filter, manufactured by PALL) to obtain a blue pigment dispersion.

(Examples 2 to 7)
The blue pigments of Examples 2 to 7 were used in the same manner as in Example 1 except that the blue refined pigments obtained in Synthesis Examples 11 to 16 were used in place of the blue refined pigment obtained in Synthesis Example 10. A dispersion was obtained.

(Comparative Example 1)
A blue pigment dispersion was obtained in the same manner as in Example 1 except that the blue refined pigment obtained in Comparative Synthesis Example 1 was used in place of the blue refined pigment obtained in Synthesis Example 10.
(Comparative Example 2)
A blue pigment dispersion was obtained in the same manner as in Example 1, except that the blue refined pigment obtained in Comparative Synthesis Example 2 was used in place of the blue refined pigment obtained in Synthesis Example 10.

(Example 8)
20.00 g (58.7 parts by weight) of pigment dispersant (trade name: BYK-LPN6919, manufactured by BYK Japan Japan Co., Ltd.), dispersion resin (trade name: Lipoxy SPC2000, solid content 40% by weight, Showa Denko Co., Ltd. )) 19.88 g (58.4 parts by weight), PMA 55.05 g (161.6 parts by weight) and PM 21.00 g (61.7 parts by weight) were put into a 500 mL internal mixer, and disperser was used. Pre-dispersion was performed by stirring for 10 minutes. A pigment comprising 31.05 g of the yellow micronized pigment obtained in Synthesis Example 17 and 3.0 g of a pigment derivative (pigment dispersing aid, sulfonated product of CI Pigment Yellow 138) was obtained in the resulting preliminary dispersion. 34.05 g (100 parts by weight) was added, and the mixture was further stirred for 10 minutes to obtain a pigment dispersion.

  To the obtained pigment dispersion, 600 g of inorganic beads having an average particle diameter of 0.8 mm (made by zirconia, trade name: Toray ceram crushed ball, manufactured by Toray Industries, Inc.) and 37.5 g of PMA were added and stirred at room temperature for 60 minutes. Then, after carrying out the first stage dispersion operation, the inorganic beads were removed from the obtained mixed dispersion using a filter (trade name: PALL HDCII Membrane Filter, manufactured by PALL). Next, 600 g of inorganic beads having an average particle diameter of 0.1 mm (made by zirconia, trade name: Toray ceram pulverized ball, manufactured by Toray Industries, Inc.) and 50 g of PM were added to the obtained pigment dispersion, and further stirred for 60 minutes. A second stage dispersion operation was performed.

  From the obtained mixed dispersion, inorganic beads were filtered off using a 2.5 μm mesh filter (trade name: PALL HDCII Membrane Filter, manufactured by PALL) to obtain a yellow pigment dispersion.

(Example 9) Preparation of blue pigment dispersion 33.75 g of pigment dispersant (BYK-LPN21116), 26.25 g (44.6 parts by weight) of resin type pigment dispersant (Lipoxy SPC2000), 55.67 g of PMA, PM 21 0.000 g, 29.1 g of blue pigment (Lionol Blue E), and 0.9 g of a pigment derivative having a sulfo group (trade name: Solsperse S12000, manufactured by Lubrizol Co., Ltd.) are placed in a 500 mL internal mixer and 10 minutes with a disper The pigment dispersion was obtained by stirring.

  To the obtained pigment dispersion, 666 g of inorganic beads having an average particle diameter of 0.8 mm (made by zirconia, trade name: Toray ceramic pulverized ball, manufactured by Toray Industries, Inc.) and 33.33 g of PMA were added and stirred at room temperature for 30 minutes. Then, after carrying out the first stage dispersion operation, the inorganic beads were removed from the obtained mixed dispersion using a filter (trade name: PALL HDCII Membrane Filter, manufactured by PALL). Next, 600 g of inorganic beads having an average particle diameter of 0.1 mm (trade name: Toray ceramic pulverized ball, manufactured by Toray Industries, Inc.) and an average weight of color filters obtained in Synthesis Example 8 were added to the obtained pigment dispersion. 75 g of a combined 5.83 wt% PM solution was added, and the mixture was further stirred for 60 minutes to carry out a second stage dispersion operation.

  From the obtained mixed dispersion, inorganic beads were removed by filtration using a 2.5 μm mesh filter (trade name: PALL HDCII Membrane Filter, manufactured by PALL) to obtain a blue pigment dispersion.

(Example 10) Preparation of yellow pigment dispersion 20.0 g of pigment dispersant (BYK-LPN21116), 30.0 g of resin-type pigment dispersant (Lipoxy SPC2000), 49.0 g of PMA, 21.00 g of PM, yellow pigment (Pariotol) 27.0 g of Yellow L0960HD) and 3.0 g of a pigment derivative (pigment dispersion aid, sulfonated product of CI Pigment Yellow 138) are charged into a 500 mL mixer and stirred with a disper for 10 minutes to give a pigment dispersion Got.

  To the obtained pigment dispersion, 600 g of inorganic beads having an average particle diameter of 0.8 mm (made by zirconia, trade name: Toray ceramic pulverized ball, manufactured by Toray Industries, Inc.) and 37.5 g of PMA were added and stirred at room temperature for 30 minutes. Then, after carrying out the first stage dispersion operation, the inorganic beads were removed from the obtained mixed dispersion using a filter (trade name: PALL HDCII Membrane Filter, manufactured by PALL). Next, 600 g of inorganic beads having an average particle diameter of 0.1 mm (trade name: Toray ceramic pulverized ball, manufactured by Toray Industries, Inc.) and an average weight of color filters obtained in Synthesis Example 8 were added to the obtained pigment dispersion. 50 g of a combined 5.83 wt% PM solution was added, and the mixture was further stirred for 60 minutes to carry out a second stage dispersion operation.

  From the obtained mixed dispersion, inorganic beads were filtered off using a 2.5 μm mesh filter (trade name: PALL HDCII Membrane Filter, manufactured by PALL) to obtain a yellow pigment dispersion.

(Comparative Example 3)
A yellow pigment dispersion was obtained in the same manner as in Example 8, except that the yellow refined pigment obtained in Comparative Synthesis Example 3 was used in place of the yellow refined pigment obtained in Synthesis Example 17.
(Comparative Example 4)
A yellow pigment dispersion was obtained in the same manner as in Example 8, except that the yellow refined pigment obtained in Comparative Synthesis Example 4 was used in place of the blue refined pigment obtained in Synthesis Example 17.

[Production of color filters]
When the viscosity of each pigment dispersion of Examples 1 to 10 and Comparative Examples 1 to 4 was measured with an E type viscometer (trade name: TV-22 type viscometer, manufactured by Toki Sangyo Co., Ltd.), It was in the range of 5-15 cps (25 ° C.). Moreover, when each pigment dispersion was dried on conditions of 130 degreeC and 1 hour, and solid content was calculated | required, all were the range of 17.5 to 18.5 weight%.

  Using each pigment dispersion of Examples 1 to 10 and Comparative Examples 1 to 4 and a binder resin (trade name: Lipoxy SPC2000, solid content 40% by weight, manufactured by Showa Denko KK), the pigment dispersion Both were mixed so that solid content: solid content of binder resin = 1: 1 (weight ratio) to prepare an SPC solution. Each of the obtained SPC liquids has a target chromaticity (y = 0.09 (in the case of blue) or y = 0.50 (in the case of yellow)) on a glass plate having a thickness of 1 mm and a square of 100 mm. It is applied with a spin coater (trade name: spin coater MS-150A, manufactured by Mikasa Co., Ltd.) so as to have a film thickness, and dried (pre-baked) at 90 ° C. for 2.5 minutes in an air bath (box dryer). The glass coating plates (color filters) of Examples 1 to 10 and Comparative Examples 1 to 4 were obtained. Depending on the viscosity of the pigment dispersion and the rotational speed of the spin coating, the thickness of the coating layer changes, and a glass coated plate having a desired chromaticity can be obtained.

[Contrast measurement]
A polarizing plate (trade name: POLAX-38S, manufactured by Luceo Co., Ltd.) was placed on the backlight, and the spacing between the polarizing plate and the glass coating plate was set to 1 mm. A rotatable polarizing plate was installed on the top. After confirming that the brightness of the backlight was sufficiently stable, the polarizing plate was adjusted to the crossed Nicols position to measure the brightness of the glass coating plate, and then rotated 90 ° to measure the brightness of the glass coating plate at the parallel position. . From the value obtained here, the contrast value was calculated based on the following equation.
(Contrast value) = (Parallel luminance) / (Cross Nicol luminance)

  For those containing a blue pigment dispersion, those having a CR value of 8000 or more are “◯ (good)”, those having a CR value of less than 8000 to 7000 are “Δ (the numerical values are slightly low, but there is no practical problem)”, A CR value of less than 7000 was evaluated as “x (defect)”. For those containing a yellow pigment dispersion, those having a CR value of 12000 or more are “O (good)”, those having a CR value of 10,000 or more and less than 12000 are “△ (the numerical value is low, which is somewhat problematic in practical use). A) ”, those having a CR value of less than 10,000 were evaluated as“ x (defective) ”. The results are shown in Table 2.

[Alkali solubility]
Using each pigment dispersion obtained in Examples 1 to 10 and Comparative Examples 1 to 4, and a photosensitive monomer (trade name: NK ester A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd.), These were mixed so that solid content: photosensitive monomer = 3.6: 1 (weight ratio) to prepare an SPC solution. Each SPC solution was applied to a 1 mm thick, 100 mm square glass plate with a spin coater (spin coater MS-150A), dried in an air bath (box dryer) at 90 ° C. for 2.5 minutes, and coated layer A glass coated plate having a thickness of 1 μm was prepared. The obtained glass coated plate was brought into contact with a 0.3N potassium hydroxide aqueous solution, and the time until the coating layer was removed was measured.

  “◯ (good)” when the removal time is 100 seconds or less, “△ (removal takes a little time, but there is no practical problem)” when the removal time exceeds 100 seconds and is 150 seconds or less, 150 It was evaluated as “× (defect)” exceeding 2 seconds. The shorter the removal time, the better the developability and the performance as a color filter. The results are shown in Table 2.

  Furthermore, in the comprehensive evaluation, when the contrast evaluation and the alkali solubility evaluation are both “○”, the evaluation is “評 価”, and either the contrast evaluation or the alkali solubility evaluation is “◯” and the other is “△”. And at least one of contrast evaluation and alkali solubility evaluation was evaluated as “×”.

Claims (6)

Polymer block containing a structural unit derived from an acrylate ester and a structural unit derived from acrylic acid, and a structural unit derived from N-vinylpyrrolidone or a structural unit derived from N-vinylpyrrolidone and a structural unit derived from acrylic acid A color filter copolymer having a weight average molecular weight of 5,000 to 20,000 and an acid value of 30 to 200 mgKOH / g. The color filter copolymer according to claim 1, wherein the acrylic ester is an acrylic ester having an alicyclic hydrocarbon group. A pigment, a pigment dispersant, the color filter copolymer according to claim 1 or 2 , and a solvent, wherein the pigment has a coating layer containing the color filter copolymer on at least a part of its surface. Pigment dispersion. It is a manufacturing method of the pigment dispersion according to claim 3 ,
A step (1) of kneading the pigment and the color filter copolymer according to claim 1 or 2 ,
A step (2) of drying and / or pulverizing the kneaded product obtained in the step (1) to obtain the pigment having a coating layer containing the color filter copolymer on its surface;
And a step (3) of obtaining a pigment dispersion by mixing a pigment having the coating layer on the surface thereof, a pigment dispersant and a solvent. In the step (1), together with the pigment and the color filter copolymer according to claim 1 or 2 , the pulverized sodium sulfate is kneaded,
In the step (2), the kneaded product obtained in the step (1) and water are mixed, the solid is separated from the obtained aqueous slurry, and the obtained solid is dried and / or pulverized. The method for producing a pigment dispersion according to claim 4 , wherein the pigment having a coating layer containing the color filter copolymer on its surface is obtained. A resist composition comprising the pigment dispersion according to claim 3 and a photosensitive compound.