JP4539477B2 - Pigment composition for color filter, method for producing the same, and color filter - Google Patents

Description

  The present invention relates to a pigment composition used for forming a color red pixel portion, a method for producing the pigment composition, and a color filter using the pigment composition.

  Examples of the pigment composition used for forming the color red pixel portion include C.I. I. Anthraquinone red pigments such as C.I. Pigment Red 177; I. A diketopyrrolopyrrole red pigment such as Pigment Red 254 is used. Anthraquinone red pigments have a bluish red hue, but a diketopyrrolopyrrole red pigment having a characteristic yellowish red hue, which is not there, has been used more recently.

  As a diketopyrrolopyrrole red pigment for forming such a color filter red pixel portion, as disclosed in Patent Document 1, a diketopyrrolopyrrole red pigment is a diketopyrrolopyrrole red pigment. A pigment composition using a sulfonic acid derivative or a sulfonamide derivative or a sulfonic acid derivative or a sulfonamide derivative of a quinacridone-based red pigment is known.

  The diketopyrrolopyrrole red pigment has a structure that contains> NH and C = O as a control, so it has the property of easily growing crystals due to hydrogen bonding. Solvent salt milling with the diketopyrrolopyrrole red pigment alone When the treatment is performed, there is a problem that the crystal growth proceeds more than the pulverization of the primary particles, and the particle diameter becomes conversely large, and the pigment has not been suitable for the salt vent salt milling treatment. However, in order to make use of such a yellowish hue, it is necessary that the colorant is composed mainly of a diketopyrrolopyrrole red pigment.

  In view of the current situation, in Patent Document 2, diketopyrrolopyrrole-based red pigment is combined with a dye derivative sharing the same pigment structure as described in Patent Document 1 or a dye derivative containing a different pigment structure, A method for producing a diketopyrrolopyrrole red pigment composition by a solvent salt milling process in which kneading equipment such as a kneader is used and mechanical grinding is performed in the presence of an organic solvent together with a grinding aid such as the above.

  However, the color filter having a red pixel portion in the diketopyrrolopyrrole red pigment composition obtained by the manufacturing method described in each of the above-mentioned patent documents has a drawback that both the luminance and contrast of the pixel portion are insufficient. was there.

JP 11-217514 A JP 2001-220520 A

  The problem to be solved by the present invention is to provide a color filter in which the luminance and contrast of the red pixel portion are both superior and a pigment composition suitable for obtaining the color filter.

  The inventors of the present invention have intensively studied a color filter having a higher brightness and contrast of the red pixel portion, a pigment composition suitable for obtaining the color filter, and a method for producing the same, which are described in the patent document. A specific amount of a specific quinacridone pigment derivative, a specific amount of the quinacridone pigment derivative is contained in an arbitrary stage, and a diketopyrrolopyrrole red pigment is subjected to a solvent salt milling treatment in the presence thereof. Has been found to be solved, and the present invention has been completed.

  That is, the present invention provides a pigment composition for a color filter containing 1 to 10 parts of a phthalimidoalkylated quinacridone per 100 parts of a diketopyrrolopyrrole red pigment in terms of mass.

  The present invention also relates to a method for producing a pigment composition for a color filter red pixel portion for solvent salt milling a diketopyrrolopyrrole pigment and a quinacridone pigment derivative. Provided is a method for producing a pigment composition for a color filter, which is used in an amount of 1 to 10 parts per 100 parts of a diketopyrrolopyrrole red pigment.

  Furthermore, the present invention relates to a liquid crystal color filter containing RGB three-color pixels and a black matrix, wherein the red pixel portion contains 1 to 10 parts of phthalimide alkylated quinacridone per 100 parts of diketopyrrolopyrrole red pigment in terms of mass. There is provided a liquid crystal color filter comprising a pigment composition, wherein a green pixel portion contains a metal halide phthalocyanine pigment, and a blue pixel portion contains an ε-type copper phthalocyanine pigment.

  Since the pigment composition for a color filter of the present invention contains a specific amount of phthalimidoalkylated quinacridone, the color filter excellent in luminance and contrast can be obtained. Moreover, in the manufacturing method of this invention, there exists an especially remarkable effect that the above-mentioned pigment composition can be manufactured simply.

The pigment composition for a color filter of the present invention contains 1 to 10 parts of phthalimidoalkylated quinacridone (B) per 100 parts of diketopyrrolopyrrole red pigment (A) in terms of mass, and has a BET specific surface area of 100 to 120 m ² / g . Hereinafter, phthalimidoalkylated quinacridone (B) is abbreviated as derivative (B).

  The diketopyrrolopyrrole pigment is a red to orange pigment having a structure represented by the following general formula, and has excellent light resistance and heat resistance. Examples of the diketopyrrolopyrrole pigment include C.I. I. Pigment Red 254, 255, 264 and 272, red pigments such as C.I. I. And orange pigments such as Pigment Orange 71 and 73. In the present invention, among these, a red pigment is used as the essential component (A). A suitable red pigment (A) is a chlorine atom in which X in the following general formula is bonded to the P (para) position. , C.I. I. Pigment Red 254.

  However, in formula, X is the same or different, and is a hydrogen atom, a chlorine atom, a phenyl group, or a methyl group.

  The derivative (B) consists of phthalimidoalkylated quinacridone. This derivative (B) is quinacridone in which at least one phthalimidoalkyl group is bonded to a hydrogen atom on the quinacridone ring. A typical phthalimidomethyl group as a phthalimidoalkyl group refers to the following group.

  Phthalimidomethylated quinacridone is a quinacridone pigment derivative having a structure represented by the following general formula.

  However, X and Y in the formula are a hydrogen atom, a methyl group or a chlorine atom which may be the same or different. The substitution number n of the phthalimidomethyl group is 1 to 3.

  Examples of such derivatives (B) include phthalimidomethylated unsubstituted quinacridone, phthalimidomethylated dimethylquinacridone, phthalimidomethylated dichloroquinacridone, and the like. These may be a single kind or a mixture of two or more kinds. As the red pigment (A), C.I. I. When Pigment Red 254 is selected, phthalimidomethylated dichloroquinacridone is preferably used as the derivative (B).

  The derivative (B) can be easily produced, for example, by reacting a quinacridone-based red pigment with paraform and phthalimide or hydroxymethylphthalimide in sulfuric acid (see JP-A-55-108466). .) As the derivative (B), a mixture of a phthalimidomethyl group-substituted phthalimidomethylated quinacridone having 1 to 3 phthalimidomethyl groups and a non-phthalimidated quinacridone red pigment can also be used. Examples of the quinacridone red pigment at this time include C.I. I. Unsubstituted quinacridone pigments such as CI Pigment Violet 19; I. Dimethylquinacridone pigments such as C.I. Pigment Red 122; I. Pigment Red 202, C.I. I. Examples thereof include dichloroquinacridone pigments such as Pigment Red 209.

  The pigment composition of the present invention is prepared by containing the red pigment (A) and the derivative (B) so that the latter is 1 to 10 parts, preferably 1 to 7 parts per 100 parts of the former in terms of mass. I can do it.

Since the pigment composition of the present invention is used for the preparation of the color filter red pixel portion, it is preferably finer than general purpose use. From such a viewpoint, the pigment composition of the present invention preferably has an average primary particle diameter of 20 nm to 80 nm. If the average particle diameter of the primary particles is 100 nm or more, the luminance of the pixel portion is lowered, which is not preferable. The average particle size of the primary particles is measured as follows. First, the particles in the field of view are photographed with a transmission electron microscope or a scanning electron microscope. And the longest length (maximum length) of the internal diameter of each particle | grain is calculated | required about 50 primary particles which comprise the aggregate on a two-dimensional image. The average value of the maximum length of each particle is defined as the average particle size of the primary particles. On the other hand, among the virtual lines that can be drawn innumerably so as to be orthogonal to the line that is the maximum length of the particles, the shortest length is set as the minimum length, and this can also be obtained for 50 pieces. The specific surface area is the BET specific surface area of the pigment composition measured by the nitrogen adsorption method, and is in accordance with “Measurement method of gas adsorption amount by one-point method” defined in Annex 2 of Japanese Industrial Standard JIS Z8830-1990. It is the specific surface area of the dried pigment composition when measured. The pigment composition of the present invention, the specific surface area of 100 ~120m ² / g.

  As for the aspect ratio, the average value of the maximum length and the average value of the minimum length of the individual particles thus obtained are obtained, and using these values, the average value of the maximum length / (average value of the minimum length) Calculate based on The pigment composition of the present invention preferably has an aspect ratio in the range of 1 to 3.

  In the pigment composition of the present invention, the red pigment (A) and the derivative (B) may be composed of particles that are not coated with the polymer (D). In order to ensure better dispersibility in a photo-curable composition such as a pigment dispersion or a resist, it is preferably coated with a polymer. In terms of mass, the polymer nonvolatile content is preferably 0.5 to 10 parts with respect to 100 parts of the red pigment (A) or derivative (B). Examples of the polymer (D) in this case include styrene- (meth) acrylic acid copolymer, styrene-butyl (meth) acrylate- (meth) acrylic acid copolymer, and (meth) acrylic acid lauryl- (meth). ) Acrylic acid copolymer, styrene- (meth) acrylic acid lauryl- (meth) acrylic acid copolymer, (meth) acrylic acid benzyl- (meth) acrylic acid copolymer, (meth) acrylic acid benzyl- (meth) ) Methyl acrylate copolymer, benzyl (meth) acrylate-methyl (meth) acrylate- (meth) acrylic acid copolymer, and the like. Among these, benzyl (meth) acrylate- (meth) acrylic acid copolymer is preferable because it is highly dispersible and a color filter with high contrast can be obtained.

  A pigment composition suitable for the present invention includes a diketopyrrolopyrrole red pigment coated with benzyl (meth) acrylate-methyl (meth) acrylate, and benzyl (meth) acrylate- (meth) acrylic. Phthalimidoalkylated quinacridone coated with an acid methyl copolymer.

  The red pigment (A) and the derivative (B) can contain a necessary amount of other red organic pigment or red organic pigment derivative (C) as necessary for the purpose of toning and the like. Examples of such other red organic pigments and red organic pigment derivatives (C) include C.I. I. Anthraquinone red pigments such as C.I. Pigment Red 177; I. Pigment Violet 19, C.I. I. Pigment Red 122, C.I. I. Pigment Red 202, C.I. I. And quinacridone red pigments such as Pigment Red 209. Examples thereof include red pigment derivatives other than the derivative (B) such as a sulfonic acid derivative of the red pigment (A) and a sulfonic acid derivative of a quinacridone-based red pigment.

  The greater the proportion of the red pigment (A) and the derivative (B) in the mixture of the red pigment (A) and the derivative (B) and the other red organic pigment or red organic pigment derivative (C), the greater the present invention. The effect of increases. Of the other red organic pigments and red organic pigment derivatives (C), taking the red pigment as an example, the red pigment (A) per 100 parts in total of the red pigment (A) and the derivative (B) in terms of mass 1 to 200 parts of a red pigment other than the above can be contained.

  These other red organic pigments and red organic pigment derivatives (C) may be similarly coated with the polymer (D) as described above.

  The pigment composition of the present invention has high dispersibility of the pigment in the medium to be colored and dispersion stability after dispersion, and the viscosity of the red pigment dispersion described below obtained by dispersing it in the liquid medium is also low and stable ( When the coating agent containing the pigment composition is applied to a base material, it can form a homogeneous coating film and obtain a colored film with high transparency.

  Further, such a pigment composition can be easily dispersed in the photocurable composition forming the color filter red pixel portion, and the light-shielding property at 365 nm, which is frequently used for curing the pigment composition, does not deteriorate. (Ie high permeability). Further, it is preferable because the photocuring sensitivity is not lowered and the film edge and pattern flow hardly occur during development. Therefore, it is possible to more easily obtain a color filter red pixel portion having high brightness, contrast, and light transmittance of a coating film that has been required in recent years. Here, the contrast is the transmitted light intensity when the object to be measured is sandwiched with the polarization directions of the two polarizing plates parallel to each other and the object to be measured is sandwiched with the polarization direction of the two polarizers perpendicular to each other. This is divided by the transmitted light intensity and is also called depolarization.

  In the pigment composition of the present invention, for example, the red pigment (A), the derivative (B), and, if necessary, the other red organic pigment or red organic pigment derivative (C) are in the mass ratio described above. Similarly, it can be manufactured by mixing in any order. In the pigment composition of the present invention, the red pigment (A) and the derivative (B) may be sufficiently mixed in advance, and another red organic pigment or red organic pigment derivative (C) may be added thereto. If necessary, ball milling, attritor, etc., before or after mixing the red pigment (A), derivative (B) and other red organic pigment or red organic pigment derivative (C) It is also possible to obtain a suitable average particle diameter of the primary particles by grinding by known and conventional means.

  However, there is a method for easily producing a pigment composition having a higher average particle diameter as described above that exhibits a higher improvement effect. It is a method of subjecting a red pigment (A) and a derivative (B) to a solvent salt milling process, that is, a method for producing a pigment composition for a color filter that performs a solvent salt milling of a diketopyrrolopyrrole pigment and a quinacridone pigment derivative. 1 to 10 parts of phthalimide alkylated quinacridone in terms of mass per 100 parts of diketopyrrolopyrrole red pigment as a quinacridone pigment derivative.

  In the present invention, the solvent salt milling means kneading and grinding an inorganic salt and an organic solvent for a mixture containing the red pigment (A) and the derivative (B) as essential components. When this treatment is performed, a crude pigment can be used as the red pigment (A).

  By this solvent salt milling process, the red pigment (A) and the derivative (B) are refined. C. I. The combination of Pigment Red 254 and phthalimidomethylated dichloroquinacridone provides optimal effects. From the pigment composition obtained by this treatment, the dispersibility in the medium to be colored and the dispersion stability therein are further improved, and a colored product having high coloring power can be obtained.

  The other red organic pigments and red organic pigment derivatives (C) described above can be included in the system at any stage of producing the pigment composition of the present invention as described above, but the red pigment (A) From the viewpoint of promoting the adsorption and the like, and thereby improving the dispersibility, it is preferable that it is preliminarily contained in the red pigment (A) or derivative (B) and then subjected to a solvent salt milling treatment.

  Therefore, the solvent salt milling treatment includes a red pigment (A) and a derivative (B) containing other red organic pigments and red organic pigment derivatives (C) and / or polymers (D), inorganic salts, and It is preferable to knead and grind an organic solvent that does not dissolve.

  As a typical method of coating the red pigment (A) and / or the derivative (B) with the polymer (D), for example, there is a method of including it before, during and after the production of the pigment composition. Specifically, for example, a method of adding and precipitating the polymer (D) to the pigment composition of the present invention not previously coated with the polymer (D), a method of adding an emulsion of the polymer (D), There is a method of kneading and grinding together with the polymer (D). In the solvent salt milling treatment, in order to sufficiently control the crystal of the red pigment (A), it is preferable to use the excellent crystal growth-inhibiting action of the derivative (B), and the polymer (D) is a red pigment (A It is preferable that the derivative (B) is not inhibited from adsorbing to the above. After the completion of crystal control, these red pigment (A), derivative (B) and the like may be coated with polymer (D).

  The solvent salt milling process can be performed by charging each of the above-described raw materials into a kneader and kneading and grinding in the kneader. Examples of the kneading means at this time include kneaders such as a kneader and a mix muller.

  As said inorganic salt, water-soluble inorganic salt can be used conveniently, For example, it is preferable to use inorganic salts, such as sodium chloride, potassium chloride, sodium sulfate. It is more preferable to use an inorganic salt having an average particle size of 0.3 to 70 μm. Such an inorganic salt can be easily obtained by pulverizing a normal inorganic salt.

  In obtaining a suitable pigment composition of the present invention, the amount of inorganic salt used is 3 to 30 parts per 1 part in total of the mixture containing the red pigment (A) and the derivative (B) as essential components in terms of mass. Of these, 7 to 30 parts, particularly 15 to 30 parts is preferable.

  Examples of the organic solvent include diethylene glycol, glycerin, ethylene glycol, propylene glycol, liquid polyethylene glycol, liquid polypropylene glycol, 2- (methoxymethoxy) ethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2- (Hexyloxy) ethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol , Dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol It can be used Lumpur and the like.

  The amount of the organic solvent used is not particularly limited, but is preferably 0.01 to 5 parts per 1 part in total of the mixture containing the red pigment (A) and the derivative (B) as essential components in terms of mass. .

  In the production method of the present invention, when performing the solvent salt milling treatment, if necessary, for the purpose of adjusting the intended hue, other red organic pigment or red organic pigment derivative (C) may be contained. I can do it.

  In the solvent salt milling process, the inorganic salt and organic solvent as described above are charged as a mixture containing the red pigment (A) and the derivative (B) as essential components after charging the necessary amount in the initial charging stage. Grinding may be performed until the required average particle size of the primary particles is reached, or only a part of the required amount is charged and milling is started, and the remaining amount of inorganic salt and / or organic solvent in the middle, You may make it grind | pulverize by charging in a lump or divided.

  The temperature during the solvent salt milling treatment is preferably 30 to 150 ° C, and more preferably 60 to 120 ° C. The time for the solvent salt milling treatment is preferably 3 hours to 36 hours, and more preferably 5 to 24 hours.

  Based on the sampling over time during the solvent salt milling, the conditions for the solvent salt milling for obtaining the pigment composition of the present invention having the required characteristics are selected based on the average primary particle size value of the primary particles in the pigment composition, etc. I can do it.

  Thus, a mixture containing the pigment composition of the present invention, an inorganic salt, and an organic solvent as main components is obtained. The organic solvent and the inorganic salt are removed from this mixture, and the solid is washed, filtered, dried, pulverized, etc. The powder of the pigment composition of this invention can be obtained by performing.

  As this cleaning method, either water washing or hot water washing can be employed. In the case of the mixture using a water-soluble inorganic salt and an organic solvent, the organic solvent and the inorganic salt can be easily removed by washing with water. It is preferable that the material having the specific conductivity is removed as much as possible. In particular, the pigment composition of the present invention for preparing the color filter pixel portion is preferably washed until the specific conductivity is 50 μS / cm or less, preferably 20 μS / cm or less.

  Examples of the drying method after washing and filtration described above include dehydration and / or desolvation of the pigment composition of the present invention containing a liquid medium by, for example, heating at 80 to 120 ° C. with a heating source installed in a dryer. And batch drying method or continuous drying method. Examples of the dryer used at that time include a box-type dryer, a band dryer, and a spray dryer.

  As a pulverization method after drying, it is not an operation for increasing the specific surface area of the pigment composition or reducing the average particle diameter of the primary particles, but when drying using a box-type dryer or a band dryer. The method is carried out in order to pulverize the pigment composition in the form of a lamp, and examples thereof include a pulverizing method using a mortar, hammer mill, disk mill, pin mill, jet mill and the like.

  The pigment composition of the present invention is preferably as the aspect ratio is close to 1. As the aspect ratio of the pigment composition increases, the dispersibility of the pigment composition in the medium to be colored and the dispersion stability therein decrease, and reaggregation of the pigment particles easily occurs. This is because, for example, when preparing a paint, a pigment dispersion prepared by using a mixture of the pigment composition of the present invention and a conventional red pigment, a composition of a photocurable compound and / or a synthetic resin containing the pigment dispersion This is not preferable in that it leads to a decrease in fluidity, storage stability, applicability to a substrate, and transparency of a coating film.

  The same can be said for the color filter pigment dispersion described later and the composition of the photocurable compound and / or synthetic resin containing the same, and the applicability to the transparent substrate for forming the color filter red pixel portion is reduced. This is not preferable in that all of the brightness, contrast, and light transmittance of the coating film in the pixel portion are lowered.

  The pigment composition of the present invention can be used for preparing a color filter red pixel portion and a red pigment for forming the red pixel portion by a conventionally known method. In producing a color filter red pixel portion using the pigment composition of the present invention, a pigment dispersion method can be suitably employed.

  A typical method in this method is a photolithography method, in which a photocurable composition to be described later is applied to a surface of a transparent substrate for a color filter provided with a black matrix and dried by heating (prebaking). After that, pattern exposure is performed by irradiating ultraviolet rays through a photomask to cure the photo-curable compound at a location corresponding to the pixel portion, and then developing the unexposed portion with a developer, thereby developing the non-pixel portion. In which the pixel portion is fixed to the transparent substrate. In this method, a pixel portion made of a cured colored film of a photocurable composition is formed on a transparent substrate.

  A photocurable composition to be described later is prepared for each color of red, green, and blue, and a color filter having red, green, and blue colored pixel portions at predetermined positions is manufactured by repeating the above-described operation. I can do it. As described above, a red pixel portion and a red pigment for forming the red pixel portion are prepared from the pigment composition of the present invention. In addition, in order to prepare the photocurable composition for forming a blue pixel part and a green pixel part, a well-known and usual blue pigment and green pigment can be used.

  Examples of the pigment for forming the blue pixel portion include C.I. I. Pigment Blue 15: 6 (ε-type copper phthalocyanine pigment) and C.I. I. Pigment Violet 23 (dioxazine violet pigment) or the like is a pigment for forming a green pixel portion. I. Pigment Green 7, 10, 36, 47, and the like. For forming the green pixel portion, C.I. I. A yellow pigment such as Pigment Yellow 150 (nickel azo complex pigment) can also be used in combination. Thereafter, if necessary, the entire color filter can be heat-treated (post-baked) in order to thermally cure the unreacted photocurable compound.

  Examples of a method for applying a photocurable composition described later on a transparent substrate such as glass include a spin coat method, a roll coat method, and an ink jet method.

  Although the drying conditions of the coating film of the photocurable composition apply | coated to the transparent substrate differ also with the kind of each component, a compounding ratio, etc., they are 50-150 degreeC and are about 1 to 15 minutes normally. This heat treatment is generally referred to as “pre-baking”. Moreover, as light used for photocuring of a photocurable composition, it is preferable to use the ultraviolet-ray of a wavelength range of 200-500 nm, or visible light. Various light sources that emit light in this wavelength range can be used.

  Examples of the developing method include a liquid piling method, a dipping method, and a spray method. After exposure and development of the photocurable composition, the transparent substrate on which the necessary color pixel portion is formed is washed with water and dried. The color filter thus obtained is subjected to heat treatment (post-baking) at 100 to 280 ° C. for a predetermined time by a heating device such as a hot plate or an oven to remove volatile components in the colored coating film, and at the same time, light The unreacted photocurable compound remaining in the cured colored film of the curable composition is thermally cured to complete the color filter.

  A photocurable composition (also called a pigment-dispersed photoresist) for forming a red pixel portion of a color filter is essential for the pigment composition of the present invention, a dispersant, a photocurable compound, and an organic solvent. It can be prepared by mixing these components as components and using a thermoplastic resin as necessary. When the colored resin film forming the red pixel portion is required to have toughness that can withstand baking performed in the actual production of a color filter, a photocurable compound is used in preparing the photocurable composition. In addition, it is essential to use this thermoplastic resin in combination. When a thermoplastic resin is used in combination, it is preferable to use an organic solvent that dissolves it.

  As a method for producing the photocurable composition, the pigment composition of the present invention, an organic solvent and a dispersant are used as essential components, and these are mixed and stirred and dispersed so as to be uniform. After preparing a pigment dispersion (also called a colored paste) for forming the red pixel part of the filter, add a photocurable compound and, if necessary, a thermoplastic resin or a photopolymerization initiator. In general, the photocurable composition is generally used.

  Examples of the dispersant include Dispervic 130, Dispersic 161, Dispersic 162, Dispersic 163, Dispersic 170 manufactured by Big Chemie, Fuka 46 and Fuka 47 manufactured by Efka, and the like. Further, a leveling agent, a coupling agent, a cationic surfactant, and the like can be used together.

  Examples of the organic solvent include aromatic solvents such as toluene, xylene and methoxybenzene, acetate solvents such as ethyl acetate and butyl acetate, propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, and ethoxyethyl propionate. Propionate solvents such as methanol, ethanol solvents such as ethanol, butyl cellosolve, ether solvents such as propylene glycol monomethyl ether, diethylene glycol ethyl ether, diethylene glycol dimethyl ether, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, hexane, etc. Aliphatic hydrocarbon solvents, N, N-dimethylformamide, γ-butyrolactam, N-methyl-2-pyrrolidone, a Phosphorus, nitrogen compound-based solvent such as pyridine, .gamma.-lactone solvents butyrolactone, carbamic acid esters such as a mixture of 48:52 of methyl carbamate and ethyl carbamate acid. As the organic solvent, polar solvents such as propionate-based, alcohol-based, ether-based, ketone-based, nitrogen compound-based, and lactone-based solvents that are water-soluble are particularly preferable. When a water-soluble organic solvent is used, water can be used in combination.

  Examples of the thermoplastic resin used for preparing the photocurable composition include urethane resins, acrylic resins, polyamic acid resins, polyimide resins, styrene maleic acid resins, styrene maleic anhydride resins, and the like. It is done.

  Examples of the photocurable compound include 1,6-hexanediol diacrylate, ethylene glycol diacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, bis (acryloxyethoxy) bisphenol A, 3-methylpentanediol di Multifunctional with relatively low molecular weight such as bifunctional monomer such as acrylate, trimethylol propaton triacrylate, pentaerythritol triacrylate, tris (2-hydroxyethyl) isocyanate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate Monofunctional, polyester acrylate, polyurethane acrylate, polyether acrylate, etc. It is.

  Examples of the photopolymerization initiator include acetophenone, benzophenone, benzyldimethylketanol, benzoyl peroxide, 2-chlorothioxanthone, 1,3-bis (4′-azidobenzal) -2-propane, 1,3-bis (4 '-Azidobenzal) -2-propane-2'-sulfonic acid, 4,4'-diazidostilbene-2,2'-disulfonic acid and the like.

  Using each of the materials as described above, the pigment composition of the present invention is, in terms of mass, uniformly 300 to 1,000 parts of an organic solvent and 0 to 100 parts of a dispersant per 100 parts. The pigment dispersion can be obtained by stirring and dispersing so that Next, in the pigment dispersion, 3 to 20 parts of the total of the thermoplastic resin and the photocurable compound per 1 part of the pigment composition of the present invention and 0.05 to 3 parts of photopolymerization start per 1 part of the photocurable compound are started. A photocurable composition for forming a color filter red pixel portion can be obtained by adding an agent and, if necessary, further an organic solvent and stirring and dispersing so as to be uniform. Such a photocurable composition is usually prepared such that the average particle diameter of the dispersed particles is 100 nm or less.

  The red pigment dispersion and photocurable composition prepared from the pigment composition of the present invention are coarse particles of 5 μm or more, preferably 1 μm or more by means of centrifugation, sintered filter, membrane filter or the like. More preferably, it is preferable to remove coarse particles of 0.5 μm or more and mixed dust.

  As the developer, a publicly known and commonly used organic solvent or alkaline aqueous solution can be used. In particular, when the photocurable composition contains a thermoplastic resin or a photocurable compound, and at least one of them has an acid value and exhibits alkali solubility, the color filter can be washed with an alkaline aqueous solution. This is effective for forming the blue pixel portion.

  Among the pigment dispersion methods, the method for producing the color filter red pixel portion by the photolithography method has been described in detail, but the color filter red pixel portion prepared using the pigment composition of the present invention has other electrodeposition methods, A color filter may be manufactured by forming a red pixel portion by a method such as a transfer method, a micellar electrolysis method, or a PVED (Photovoltaic Electrodeposition) method.

  The color filter is composed of a blue pigment composition, a green pigment composition, and a photocurable composition of each color obtained by using the pigment composition of the present invention that is red, and a liquid crystal between a pair of parallel transparent electrodes. The material is encapsulated, and the transparent electrode is divided into discontinuous fine sections, and red (R), green (G) and blue ( B) Obtained by providing a color filter coloring pixel portion selected from any one of the colors alternately in a pattern, or by forming a color filter coloring pixel portion on a substrate and then providing a transparent electrode. I can do it.

  As the color filter of the present invention, in the liquid crystal color filter containing RGB three-color pixels and a black matrix, the red pixel portion contains the pigment composition as described above, and the green pixel portion is a metal halide phthalocyanine pigment. And a blue pixel portion containing an ε-type copper phthalocyanine pigment is preferable from the viewpoint of a wider color gamut that can be reproduced.

  Of course, if necessary, the red pixel portion may further include an anthraquinone red pigment, the green pixel portion may further include a nickel azo complex pigment, and the blue pixel portion may further include a dioxazine billet pigment. You can also

  The color filter pigment composition of the present invention is used in various known and conventional applications such as paint, plastic (resin molded product), printing ink, rubber, leather, electrostatic image developing toner, inkjet recording ink, thermal transfer. It can also be applied to coloring inks and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited by this. In Examples and Comparative Examples, “%” is based on mass.

(Synthesis example)
A reaction vessel was charged with 800 parts of cyclohexanone, heated to 100 ° C. while injecting nitrogen gas into the vessel, and a mixture of the following monomer and thermal polymerization initiator was added dropwise at the same temperature over 1 hour to carry out a polymerization reaction.

Benzyl methacrylate 50.0 parts Methyl methacrylate 50.0 parts Azobisisobutyronitrile 10.0 parts After the addition, the mixture was further reacted at 100 ° C for 3 hours, and then 2.0 parts of azobisisobutyronitrile was added to cyclohexanone 50 What was dissolved in part was added, and the reaction was further continued at 100 ° C. for 1 hour to synthesize a resin solution. After cooling to room temperature, about 2 g of the resin solution was sampled, heated and dried at 180 ° C. for 20 minutes to measure the nonvolatile content, and cyclohexanone was added to the previously synthesized resin solution so that the nonvolatile content was 20%. An acrylic resin solution was prepared.

100 parts of untreated diketopyrrolopyrrole red pigment (CI Pigment Red 254), phthalimidomethylated dichloroquinacridone (mixture of 83% of mono-, di- and tri-substituted phthalimidomethyl groups prepared according to a conventional method) ) 5 parts, 1,000 parts of sodium chloride, and 200 parts of diethylene glycol were charged into a stainless steel 2 L kneader (manufactured by Inoue Seisakusho Co., Ltd.) and kneaded at 90 ° C. for 8 hours. The mixture is then poured into 2 liters of warm water and stirred for about 1 hour while heating to about 80 ° C. to form a slurry, which is filtered and washed repeatedly until the specific conductivity is 50 μS / cm or less. Then, it was dried at 90 ° C. for one day and night to obtain 102 parts of a red pigment composition for a color filter (primary particle diameter 20 to 30 nm, specific surface area 105 m ² / g, aspect ratio 1 to 3).

Instead of phthalimidomethylated dichloroquinacridone, the same amount of phthalimidomethylated unsubstituted quinacridone (a mixture of mono-, di- and tri-substituted phthalimidomethyl groups prepared in accordance with a conventional method in the range of 70 to 85%) is used. Except for the above, the same operation as in Example 1 was carried out to obtain 101 parts of a red pigment composition for a color filter (primary particle diameter 20 to 30 nm, specific surface area 100 m ² / g, aspect ratio 1 to 3).

Instead of phthalimidomethylated dichloroquinacridone, the same amount of phthalimidomethylated dimethylquinacridone (a mixture of mono-, di- and tri-substituted phthalimidomethyl groups prepared according to a conventional method of 70 to 85%) was used, The same operation as in Example 1 was performed to obtain 101 parts of a red pigment composition for a color filter (primary particle diameter 20 to 30 nm, specific surface area 100 m ² / g, aspect ratio 1 to 3).

Example 1 except that 50 parts of untreated diketopyrrolopyrrole red pigment and 50 parts of untreated anthraquinone pigment (CI Pigment Red 177) were used in place of 100 parts of untreated diketopyrrolopyrrole red pigment. The same operation was performed to obtain 102 parts of a red pigment composition for a color filter (primary particle diameter 20 to 30 nm, specific surface area 105 m ² / g, aspect ratio 1 to 3).

100 parts of untreated diketopyrrolopyrrole red pigment (CI Pigment Red 254), 5 parts of phthalimidomethylated dichloroquinacridone, benzyl (meth) acrylate-methyl (meth) acrylate copolymer (nonvolatile) Min) 5 parts, 1000 parts of sodium chloride, and 200 parts of diethylene glycol were charged into a stainless steel 2 L kneader (manufactured by Inoue Seisakusho) and kneaded at 90 ° C. for 8 hours. The mixture is then poured into 2 liters of warm water and stirred for about 1 hour while heating to about 80 ° C. to form a slurry, which is filtered and washed repeatedly until the specific conductivity is 50 μS / cm or less. Then, it was dried at 90 ° C. for one day and night to obtain 102 parts of a red pigment composition for a color filter (primary particle diameter 20 to 30 nm, specific surface area 110 m ² / g, aspect ratio 1 to 3).

[Comparative Example 1]
The same operation as in Example 1 was carried out except that 5 parts of the phthalimidomethylated dichloroquinacridone was not added, to obtain a red pigment for color filter (primary particle diameter 30 to 40 nm, specific surface area 80 m ² / g).

[Comparative Example 2]
In place of 5 parts of the phthalimidomethylated dichloroquinacridone, derivatives i of JP 2001-220520 A [C.I. I. For the benzene ring of Pigment Red 255 _- the same amount of _{(CH 2) 6 N (C} 2 H 5) 2 mixture sum of mono- and di-substituted product (diethylamino hexyl group) is in the range 70-85%] The same operation as in Example 1 was carried out except that it was used to obtain 102 parts of a red pigment composition for a color filter (primary particle size 30 to 40 nm, specific surface area 88 m ² / g).

  Using the red pigment composition for color filter obtained in Example 1 as a red pigment, a color filter red pixel portion was produced by photolithography.

  As a method for producing the color filter red pixel portion, 10 parts of a red pigment composition for a color filter, 2.5 parts of N, N′-dimethylformamide (organic solvent), Dispersic 161 (dispersant manufactured by Big Chemie) 6.78 Part, 80.80 parts of Euker Ester EEP (Union Carbide organic solvent) is added with 0.5 mmφ Sepul beads, and dispersed with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.) for 1 hour to obtain a pigment dispersion (colored paste). Obtained. 75.00 parts of this pigment dispersion, Aronix M7100 (polyester acrylate resin, produced by Toa Gosei Chemical Co., Ltd., equivalent to a photocurable compound), 5.50 parts, KAYARAD DPHA (dipentaerylate hexaacrylate) , Equivalent to a photocurable compound manufactured by Nippon Kayaku Co., Ltd.) 5.00 parts, KAYACURE BP-100 (benzophenone, manufactured by Nippon Kayaku Co., Ltd., corresponding to a photopolymerization initiator) 1.00 Part and 13.5 parts of Euker ester EFP were stirred with a dispersion stirrer to obtain a photocurable composition for forming a color filter red pixel part. The composition was applied to 1 mm thick glass so as to have a dry film thickness of 1 μm.

  Next, pattern exposure with ultraviolet rays was performed through a photomask, and then the unexposed portion was washed with an organic solvent to produce a color filter red pixel portion.

  A color filter red pixel portion was produced in the same manner as in Example 6 except that the red pigment composition for color filter obtained in Example 2 was used as a red pigment.

  A color filter red pixel portion was produced in the same manner as in Example 6 except that the red pigment composition for color filter obtained in Example 3 was used as a red pigment.

  A color filter red pixel portion was produced in the same manner as in Example 6 except that the red pigment composition for color filter obtained in Example 4 was used as a red pigment.

  A color filter red pixel portion was manufactured in the same manner as in Example 6 except that the red pigment composition for color filter obtained in Example 5 was used as a red pigment.

Comparative Example 3
A color filter red pixel portion was manufactured in the same manner as in Example 6 except that the red pigment for color filter obtained in Comparative Example 1 was used as a red pigment.

Comparative Example 4
A color filter red pixel portion was produced in the same manner as in Example 6 except that the red pigment composition for color filter obtained in Comparative Example 2 was used as a red pigment.

  The brightness, contrast, and light transmittance of the coating films of the produced color filter red pixel portions of Examples 6 to 10 and Comparative Examples 3 to 4 were evaluated. The results are shown in Table 1.

  Luminance (Y value) is calculated by using a micro-spectrophotometer MCPD-3000 manufactured by Otsuka Electronics Co., Ltd. to calculate chromaticity coordinate x value and y value by F10 light source colorimetry. The Y value in CIE color development system chromaticity was measured by combining the values. Here, it was evaluated that the visual brightness was higher as the luminance (Y value) was higher. In contrast, the color filter red pixel portion was installed between two polarizing plates, a light source was installed on one side, and a CCD camera was installed on the opposite side to measure the luminance. It was calculated from the ratio of luminance (transmitted light intensity) between when the polarization axis was parallel and when it was vertical.

  The light transmittance is measured at the initial rise of the light transmittance of the spectral transmittance spectrum by using the first color spectrophotometer (the spectrophotometer described above) defined in JIS Z 8722 for the color filter red pixel portion. The light transmittance at a wavelength (λmax = 620 nm) was measured.

Table 1

  As is clear from the results in Table 1, in the red pixel portions of the color filters of Examples 6 to 10, a photocurable composition excellent in dispersibility and dispersion stability was obtained in a shorter time with extremely weak pigment aggregation. The red pixel portion that can be prepared and obtained therefrom has high brightness, contrast, and light transmittance of the coating film.

On the other hand, in the color filter red pixel portion of Comparative Examples 1 and 2, a photocurable composition having strong pigment aggregation and poor dispersibility and dispersion stability is prepared. The brightness, contrast, and light transmittance were all low.

Claims (7)

A pigment composition for a color filter, characterized by having a BET specific surface area of 100 to 120 m ² / g containing 1 to 10 parts of phthalimidoalkylated quinacridone per 100 parts of diketopyrrolopyrrole red pigment in terms of mass. The pigment composition according to claim 1, wherein the phthalimidoalkylated quinacridone is phthalimidomethylated dichloroquinacridone. Diketopyrrolopyrrole red pigment coated with benzyl (meth) acrylate-methyl (meth) acrylate and phthalimide coated with benzyl (meth) acrylate-methyl (meth) acrylate copolymer The pigment composition according to claim 1 or 2, comprising an alkylated quinacridone. In a method for producing a pigment composition for a color filter that performs solvent salt milling of a diketopyrrolopyrrole pigment and a quinacridone pigment derivative, as a quinacridone pigment derivative, phthalimide alkylated quinacridone is converted into a diketopyrrolopyrrole red pigment 100 in terms of mass. The method for producing a pigment composition for a color filter according to claim 1, wherein 1 to 10 parts per part is used. The method for producing a pigment composition according to claim 4, wherein the phthalimidoalkylated quinacridone is phthalimidomethylated dichloroquinacridone. The method for producing a pigment composition according to claim 4 or 5, further comprising coating a diketopyrrolopyrrole red pigment and a phthalimidoalkylated quinacridone with a benzyl (meth) acrylate-methyl (meth) acrylate copolymer. In a liquid crystal color filter containing RGB three-color pixels and a black matrix, the red pixel portion contains the pigment composition according to any one of claims 1 to 3, and the green pixel portion is a metal halide phthalocyanine pigment. And a blue pixel portion contains an ε-type copper phthalocyanine pigment.