WO2015079727A1 - Color filter pigment composition, production method thereof, and color filter - Google Patents

Abstract

The purpose of the present application is to provide a color filter pigment composition which has high heat resistance and enables display with excellent brightness and contrast, and also to provide a production method thereof, and a color filter comprising said pigment composition. The pigment composition comprises a copper phthalocyanine pigment, a zinc phthalocyanine pigment, and a resin having an epoxy group; the production method is based on solvent salt milling of said pigment composition; and the color filter comprises said pigment composition and enables display with high brightness and contrast.

Description

Color filter pigment composition, method for producing the same, and color filter

When used as a color filter, the present invention uses a color filter pigment composition having high heat resistance and excellent brightness and contrast, a method for producing the color filter pigment composition, and the color filter pigment composition. It relates to a color filter.

The color filter of the liquid crystal display device has a red pixel portion (R), a green pixel portion (G), and a blue pixel portion (B). Each of these pixel portions has a structure in which a thin film of a synthetic resin in which an organic pigment is dispersed is provided on a substrate, and organic pigments of red, green, and blue are used as the organic pigment.

Among these pixel portions, as a blue organic pigment for forming a blue pixel portion, an ε-type copper phthalocyanine pigment (CI Pigment Blue 15: 6) is generally used, and the color is adjusted as necessary. Therefore, a small amount of purple organic pigment dioxazine violet pigment (CI Pigment Violet 23) is used in combination.

The organic pigment used to create the color filter has characteristics that are completely different from those of conventional general-purpose applications. Specifically, the display screen of the liquid crystal display device can be seen more clearly (high contrast), or the same display screen. There is a demand for making the image brighter (higher brightness).

In order to meet such demands, powdered organic pigments that have been refined to have an average primary particle size of 100 nm or less are frequently used. In addition, since the color filter is generally baked at a high temperature of 100 to 280 ° C., the organic pigment to be used is required to have heat resistance, and an organic pigment that does not decrease the contrast and brightness even after baking is required. Has been.

Specifically, Patent Document 1 proposes that a good ink and paint having a high coloring power and a wide display area can be obtained, characterized by containing an aluminum phthalocyanine pigment and zinc phthalocyanine. Similarly, Patent Document 2 proposes that an electrophotographic image capable of forming a clear and transparent image can be obtained by a composite pigment made of a mixture or solid solution of copper phthalocyanine and aluminum phthalocyanine. Furthermore, Patent Document 3 proposes a blue pigment composition for a color filter containing an ε-type copper phthalocyanine pigment and a zinc phthalocyanine pigment, and a color filter containing them, suitable for an LED or organic EL backlight light source.

However, the copper phthalocyanine and aluminum phthalocyanine as described in Patent Documents 1 and 2 have low brightness and contrast when used in a color filter, and only the mixed pigment of copper phthalocyanine and zinc phthalocyanine described in Patent Document 3 is used. The heat resistance was inferior, and the luminance and contrast could not reach sufficient required levels.

JP 2007-204658 A JP 2001-89682 A JP 2011-180365 A

An object of the present invention is to provide a color filter pigment composition having high heat resistance and capable of displaying with excellent brightness and contrast, a method for producing the same, and a color filter comprising the pigment composition.

As a result of intensive studies in view of the above-mentioned circumstances, the present inventors can display with high brightness and contrast value by using a pigment composition comprising a copper phthalocyanine pigment, a zinc phthalocyanine pigment and a resin having an epoxy group. The present inventors have found that a color filter can be obtained and have completed the present invention.

That is, the present invention provides a color filter pigment composition comprising a copper phthalocyanine pigment, a zinc phthalocyanine pigment, and a resin having an epoxy group.

The present invention also relates to a resin having an epoxy group, the content of copper phthalocyanine pigment being 65 to 94.9 parts, the content of zinc phthalocyanine pigment being 0.1 to 15 parts, out of 100 parts of the pigment composition in terms of mass. The color filter pigment composition as described above, wherein the content of is 5 to 20 parts.

The present invention also provides the color filter pigment composition as described above, wherein the copper phthalocyanine is ε-type copper phthalocyanine.

The present invention also provides the color filter pigment composition as described above, wherein the epoxy group-containing resin has an epoxy equivalent of 200 to 2000 and a weight average molecular weight of 500 to 20000.

The present invention also provides the production of a pigment composition for a color filter according to any one of the above, which comprises a step of kneading a mixture of a copper phthalocyanine pigment, a zinc phthalocyanine pigment and a resin having an epoxy group together with a water-soluble inorganic salt and a water-soluble organic solvent. Provide a method.

Furthermore, the present invention provides a color filter comprising the color filter pigment composition described above or a color filter pigment composition obtained by the production method.

The pigment composition for a color filter of the present invention contains a zinc phthalocyanine pigment in addition to a conventional copper phthalocyanine pigment, and further comprises an epoxy group-containing resin, so when used in a color filter, it has high heat resistance, brightness, There is a particularly remarkable technical effect that enables display with high contrast.

In addition, the method for producing a pigment composition for a color filter according to the present invention is uniform because a resin having copper phthalocyanine, zinc phthalocyanine and an epoxy group is kneaded together with a water-soluble inorganic salt and a water-soluble organic solvent (solvent salt milling). It has a particularly remarkable technical effect that a pigment composition that has a fine particle size and can provide a color filter that can display more excellent brightness and contrast can be easily obtained.

Hereinafter, details of the present invention will be described.

The present invention is a color filter pigment composition containing a copper phthalocyanine pigment, a zinc phthalocyanine pigment, and a resin having an epoxy group, a method for producing the same, and a color filter comprising the pigment composition.

In the present invention, the copper phthalocyanine pigment is used as a blue colorant such as normal ink, paint, plastic, etc. I. Ε type which is CI Pigment Blue 15: 6 is used, and any known ones can be used. Such a copper phthalocyanine pigment is, for example, wet milling crude copper phthalocyanine, wet milling a mixture of ε-type copper phthalocyanine and α-type copper phthalocyanine obtained by dry milling, or as required. It can be easily obtained by wet milling a mixture of ε-type copper phthalocyanine seed particles and α-type copper phthalocyanine. Of course, when an ε-type copper phthalocyanine pigment is obtained by the production method as described above, a commercially available ε-type copper phthalocyanine pigment can also be used as the ε-type copper phthalocyanine used as the raw material.

The zinc phthalocyanine pigment is a phthalocyanine pigment having a structure in which copper, which is a central metal of a copper phthalocyanine pigment, is substituted with zinc. Zinc phthalocyanine itself is a known substance, and can be produced, for example, by heating and stirring phthalodinitrile and a catalyst in an organic solvent under an inert gas, adding zinc chloride thereto, and raising the temperature. The reaction mixture containing zinc phthalocyanine thus obtained can be filtered, washed, and dried as necessary to obtain crude zinc phthalocyanine. Zinc phthalocyanine pigments are known and publicly used pigments, such as wet milling crude zinc phthalocyanine, wet milling zinc phthalocyanine obtained by dry milling, or dissolving it in sulfuric acid and depositing it in water. It can be easily obtained by the conversion operation. As the zinc phthalocyanine pigment, α, β, and ε types are known, and all known crystal types can be used in the present invention.

The resin having an epoxy group used in the present invention plays a role for improving the dispersibility of the pigment into fine particles, heat resistance, suppression of pigment particle growth, and dispersion and resist material. Examples of the resin having an epoxy group include bisphenol A type epoxy resin, bisphenol F type epoxy resin, or those hydrogenated to them; orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, p -Glycidyl ester epoxy resin such as hydroxybenzoic acid glycidyl ester, tetrahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, trimellitic acid triglycidyl ester; ethylene glycol diglycidyl Ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethyl Glycidyl ether-based epoxy resins such as propane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, polyglycidyl ether of sorbitol, polyglycidyl ether of polyglycerol; triglycidyl isocyanurate, Examples include, but are not limited to, glycidylamine-based epoxy resins such as tetraglycidyldiaminodiphenylmethane; linear aliphatic epoxy resins such as epoxidized polybutadiene and epoxidized soybean oil, and the like. In addition, novolac type epoxy resins such as phenol novolac epoxy resin, o-cresol novolac epoxy resin, bisphenol A novolac epoxy resin and the like can also be used.

Further, as examples of resins having an epoxy group, brominated bisphenol A type epoxy resins imparted with flame retardancy, phosphorus-containing epoxy resins, dicyclopentadiene skeleton-containing epoxy resins, naphthalene skeleton-containing epoxy resins, anthracene-type epoxy resins, tertiary A butylcatechol type epoxy resin, a triphenylmethane type epoxy resin, a tetraphenylethane type epoxy resin, a biphenyl type epoxy resin, a bisphenol S type epoxy resin, or the like can be used.

Furthermore, as the resin having an epoxy group, a vinyl copolymer containing an epoxy group may be used in addition to the so-called epoxy resin mentioned above. For example, a vinyl copolymer of glycidyl methacrylate and another compound having a double bond can be mentioned.

The epoxy equivalent of the resin having an epoxy group used in the present invention is preferably 200 to 2,000. When the epoxy equivalent exceeds 2000, the content of the epoxy group is small, so that the pigment is not finely divided and the heat resistance is insufficient. If the epoxy equivalent is less than 200, the heat resistance of the pigment composition may decrease due to the heat resistance of the resin itself.

The weight average molecular weight of the resin having an epoxy group used in the present invention is preferably 500 to 20000. When the weight average molecular weight is less than 500, the effect of refining the pigment may be reduced. When the weight average molecular weight exceeds 20000, the viscosity of the colored composition is increased, and the contrast and brightness may be decreased.

The blue pigment composition for a color filter of the present invention can be prepared by containing the copper phthalocyanine pigment, the zinc phthalocyanine pigment, and the resin having an epoxy group in an arbitrary mass ratio, specifically, in terms of mass. Of 100 parts of the pigment composition, the content of copper phthalocyanine pigment is 65 to 94.9 parts, the content of zinc phthalocyanine pigment is 0.1 to 15 parts, and the content of resin having an epoxy group is 5 to 20 parts. Further, the copper phthalocyanine pigment content is 75 to 94 parts, the zinc phthalocyanine pigment content is 1 to 10 parts, and the epoxy group content is 5 to 15 parts. It is more preferable that the luminance and contrast can be increased in the display of the color filter.

The blue pigment composition for a color filter of the present invention may contain a phthalocyanine derivative different from the copper phthalocyanine pigment and the zinc phthalocyanine pigment. As such phthalocyanine derivatives, metal phthalocyanine sulfonic acid, sulfonamidated metal phthalocyanine, phthalimidomethylated metal phthalocyanine, carboxybenzamidomethylated metal phthalocyanine, or metal salts, ammonia salts, amine salts, etc. of the aforementioned derivatives can be used. I can do it. In particular, carboxybenzamidomethylated metal phthalocyanine, its polyvalent metal salt or phthalimidomethylated metal phthalocyanine can be expected to have sufficient contrast and luminance heat resistance in the resulting blue pigment composition, and to the hue. This is preferable because the influence is small. In addition, an effect of crystal control can be expected at the time of solvent salt milling described later.

The above phthalocyanine derivative can be used in an amount of 0.1 to 15 parts, preferably 1 to 10 parts, based on mass, when the total of copper phthalocyanine pigment and zinc phthalocyanine pigment is 100.

The copper phthalocyanine pigment and zinc phthalocyanine pigment and other phthalocyanine derivatives used as necessary may have the same small particle diameter and high purity, so that the performance of the blue pixel part finally obtained is improved. This is preferable.

The particle size of the blue pigment composition for a color filter of the present invention is not particularly limited, but the average particle size of primary particles is 10 to 50 nm in order to enable high contrast and high luminance. In particular, the average particle diameter of the primary particles is particularly preferably 10 to 30 nm because stable production of the color filter is facilitated.

In the present invention, the average particle diameter of primary particles is measured as follows. First, the particle | grains in a visual field are image | 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 of the 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, the shortest length of the imaginary lines that can be drawn innumerably so as to be orthogonal to the line that becomes the maximum length of the particles is set as the minimum length, and this can also be obtained for 50 pieces. 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

A vertical / horizontal aspect ratio of 4 or less is preferable because it contributes to improving the viscosity characteristics of pigment dispersions and color resists, improves fluidity, and contributes to the improvement of contrast when used as a color filter.

The pigment composition for a color filter of the present invention can be prepared by mixing the copper phthalocyanine pigment, the zinc phthalocyanine pigment, a resin having an epoxy group, and, if necessary, a phthalocyanine derivative. Copper phthalocyanine pigment in that a blue pigment composition capable of obtaining a blue pixel portion of a color filter capable of displaying a liquid crystal with a higher luminance than that prepared by simply mixing each component can be easily obtained. A blue pigment composition for a color filter comprising a step of solvent salt milling a mixture containing a zinc phthalocyanine pigment and a resin having an epoxy group as an essential component and also containing a phthalocyanine derivative as necessary. preferable.

Solvent salt milling means that an organic pigment, a water-soluble inorganic salt, and a hydrophilic organic solvent that does not dissolve the organic pigment are charged into a kneader and kneaded and ground therein. As a kneader at this time, for example, a kneader, a mix muller, or the like can be used.
In the present invention, a zinc phthalocyanine pigment can be used together with a copper phthalocyanine pigment as the organic pigment. Moreover, together with an organic pigment, a water-soluble inorganic salt, and a hydrophilic organic solvent, a resin having an epoxy group can be charged into a kneader and kneaded and ground.

In this solvent salt milling, crude copper phthalocyanine other than β-type can be used as the copper phthalocyanine pigment.

As the copper phthalocyanine other than β-type used in the solvent salt milling, copper phthalocyanine other than β-type capable of generating ε-type is preferable, and may be ε-type copper phthalocyanine, which may be α-type, γ-type, δ-type, π It may be copper phthalocyanine selected from the group consisting of type, ρ type, X type, and R type.

Among these, copper phthalocyanine selected from the group consisting of α-type, γ-type, ε-type, and δ-type is preferable.

As the copper phthalocyanine other than the β-type, a copper phthalocyanine pigment other than the β-type having a smaller particle diameter may be used, or a crude copper phthalocyanine other than the β-type may be used after dry grinding, and the β-type Copper phthalocyanine other than β-type obtained in advance by wet milling a mixture of copper phthalocyanine seed particles and α-type copper phthalocyanine may be used.

Any known and commonly used copper phthalocyanines other than the β-type can be used.

Also, when copper phthalocyanine other than β-type and ε-type is used for solvent salt milling, it is preferable to add a small amount of ε-type copper phthalocyanine as seed particles because the crystal transition time is shortened.

Here, the ε-type copper phthalocyanine used as seed particles can be used with any ε conversion rate. However, it is preferable to use ε-type copper phthalocyanine having no other crystal form as much as possible. The ε-type copper phthalocyanine used as the seed particles is preferably 0.05 to 10 parts by mass, more preferably 5 to 8 parts by mass per 100 parts of copper phthalocyanine other than β-type and ε-type, because production time is reduced.

As the zinc phthalocyanine pigment, a zinc phthalocyanine pigment having a smaller particle diameter may be used, or crude zinc phthalocyanine may be used after dry grinding.

The resin having an epoxy group is preferably in a solid form, and is preferably in the form of a powder that is further pulverized even in a solid state due to a kneading process using a kneader. Preferably, the use of a granular resin pulverized to a particle size of 5 mmΦ or less makes it possible to make the pigment and inorganic salt uniform at an early stage. In the case of a resin dissolved in an organic solvent or water, after the solvent is distilled off, the resin can be dried to a solid state. Further, even a resin in which a solvent or water remains can be used as long as it does not affect the solubility of the inorganic salt.

As the inorganic salt, a water-soluble inorganic salt can be preferably used. For example, an inorganic salt such as sodium chloride, potassium chloride, sodium sulfate is preferably used. It is more preferable to use an inorganic salt having an average particle size of 0.5 to 50 μm. Such an inorganic salt can be easily obtained by pulverizing a normal inorganic salt.

Conventionally, since a fine pigment composition is suitably used for forming a pixel portion of a color filter, the amount of inorganic salt used relative to the amount of copper phthalocyanine pigment used in solvent salt milling is used to obtain this suitable pigment composition. Is preferably high. That is, the amount of the inorganic salt used is preferably 5 to 30 parts, more preferably 7 to 20 parts, based on 1 part of the copper phthalocyanine pigment.

As the organic solvent, an organic solvent capable of suppressing crystal growth is preferably used, and as such an organic solvent, a water-soluble organic solvent can be suitably used. For example, 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 mono Butyl ether, triethylene glycol, triethylene glycol monomethyl ether, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene group Call, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, can be used dipropylene glycol.

The amount of the water-soluble organic solvent used in this case is not particularly limited, but is preferably 0.1 to 0.4 part, preferably 0.15 to 0.30 part based on 1 part of the inorganic salt in terms of mass. Is more preferable.

The temperature at the time of solvent salt milling is preferably 30 to 150 ° C, more preferably 80 to 100 ° C. The solvent salt milling time is preferably 5 to 20 hours, more preferably 8 to 18 hours.

Thus, a mixture containing a copper phthalocyanine pigment, a zinc phthalocyanine pigment, a resin having an epoxy group, an inorganic salt, and an organic solvent as a main component is obtained. The organic solvent and the inorganic salt are removed from this mixture, and copper phthalocyanine is removed as necessary. A fine pigment composition powder can be obtained by washing, filtering, drying, pulverizing, etc., a solid mainly composed of pigment and zinc phthalocyanine pigment.

As washing, either water washing or hot water washing can be adopted. The number of washings can be repeated in the range of 1 to 5 times. In the case of the mixture using a water-soluble inorganic salt and a water-soluble organic solvent, the organic solvent and the inorganic salt can be easily removed by washing with water.

The blue pigment composition for a color filter of the present invention contains a copper phthalocyanine pigment, a zinc phthalocyanine pigment, a resin having an epoxy group, and other organic impurities other than these phthalocyanine derivatives used in combination as necessary. The content is preferably used after being purified to be as close to zero as possible. Further, it is preferable to use it after purification so that free halogen ions and metal ions are as close to zero as possible. For example, the standard of cleaning is until the specific conductivity of the cleaning water becomes equal to or less than the specific conductivity of the raw water + 20 μS / cm. In this purification, purification by ion exchange membrane can be used in addition to purification by alkali washing and acid washing.

Examples of the drying after filtration and washing described above include batch or continuous drying in which the pigment is dehydrated and / or desolventized by heating at 80 to 120 ° C. with a heating source installed in a dryer. Examples of the dryer generally include a box dryer, a band dryer, and a spray dryer. In addition, the pulverization after drying is not an operation for increasing the specific surface area or reducing the average particle diameter of the primary particles. For example, as in the case of drying using a box dryer or a band dryer, the pigment is used. Is performed to break the pigment into a powder when it becomes a lamp or the like, and examples thereof include mortar, hammer mill, disk mill, pin mill, jet mill and the like.

In addition, when a suitable blue pigment composition as described above is used for forming a pixel portion of a color filter, the light shielding property at 365 nm, which is frequently used when the photosensitive composition is cured, is not reduced. This is preferable because there is no decrease in curing sensitivity and film edge and pattern flow hardly occur during development.

The blue pigment composition of the present invention has high dispersibility and dispersion stability in a liquid medium, and the blue pigment dispersion and blue curable resin composition described below are stable with low viscosity (dispersed in fine particles). Therefore, when a color filter blue pixel portion is manufactured, a uniform coating film can be formed to obtain a color filter having high brightness, contrast and light transmittance.

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. Divided by transmitted light intensity.

Further, the pigment composition of the present invention only needs to contain copper phthalocyanine pigment, zinc phthalocyanine pigment, and resin having an epoxy group as essential components, and only these may be used as the blue pigment of the color filter blue pixel portion. Although it is good, if necessary, the above phthalocyanine derivatives and C.I. I. An organic pigment such as a dioxazine violet pigment such as CI Pigment Villet 23 may be further used in combination. These can be included in the preparation at any stage in the preparation of the pigment composition to the preparation of the photocurable composition described below.

The blue pigment composition of the present invention can be used for forming a color filter by a conventionally known method. In producing a color filter using this pigment composition, 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 is heated and dried (prebaked). Then, pattern exposure is performed by irradiating ultraviolet rays through a photomask to cure the photocurable composition at a location corresponding to the pixel portion, and then developing the unexposed portion with a developer. In this method, the pixel portion is removed and 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. In addition, from the blue pigment composition of the present invention, both negative and positive photocurable compositions can be prepared.

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. A blue pixel portion can be formed from the pigment composition of the present invention. In addition, in order to prepare the photocurable composition for forming a red pixel part and a green pixel part, a well-known and usual red pigment and green pigment can be used.

As a pigment for forming the red pixel portion, for example, C.I. I. Pigment Red 177, 209, 254, and the like are pigments for forming the green pixel portion, for example, C.I. I. Pigment Green 7, 10, 36, 47, 58 and the like. A yellow pigment can be used in combination for forming the red pixel portion and the green pixel portion. Thereafter, if necessary, the entire color filter can be heat-treated (post-baked) in order to thermally cure the unreacted photocurable composition.

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

The drying conditions of the coating film of the photocurable composition applied to the transparent substrate vary depending on the type of each component, the blending ratio, etc., but are usually from 50 to 150 ° C. for about 1 to 15 minutes. This heat treatment is generally referred to as “pre-baking”. Further, as the light used for photocuring the photocurable composition, it is preferable to use ultraviolet rays or visible light in the wavelength range of 200 to 500 nm. 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 a 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.

The photocurable composition for forming the color filter is composed of the blue pigment composition of the present invention, a dispersant, a photocurable compound, and an organic solvent as essential components, and a thermoplastic resin is used as necessary. It can be prepared by mixing these. When the colored resin film that forms the blue pixel portion requires toughness that can withstand baking, etc. 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 blue 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 blue pigment dispersion for forming the blue pixel portion of the color filter, the photocurable resin is added with a photocurable compound and, if necessary, a thermoplastic resin or a photopolymerization initiator. A method of forming a composition is common.

Examples of the dispersing agent include DisperBYK130, 161, 162, 163, 170, BYK LPN21116 manufactured by Big Chemie, EFKA46, EFKA47 manufactured by Efka, Ajisper PB814 manufactured by Ajinomoto Finetech, and PB821. Can be mentioned. Moreover, a leveling agent, a coupling agent, various surfactants, etc. can be used together.

As such a dispersant, (1) those having excellent dispersibility can lower the viscosity of the dispersion and can further reduce the average particle size in the dispersion, thereby further increasing the contrast before firing. It is preferable because it can be increased, and (2) a material having excellent heat resistance is preferable because the reduction range of contrast and luminance after firing can be further reduced.

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 methanol, ether solvents such as butyl cellosolve, 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, Diphosphate, 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.

The organic solvent is preferably a polar solvent such as propionate, alcohol, ether, ketone, nitrogen compound, or lactone, which is water-soluble. When a water-soluble organic solvent is used, water can be used in combination.

Examples of the thermoplastic resin used for the preparation of the photocurable composition include urethane resins, acrylic resins, polyamide resins, polyimide resins, styrene maleic acid resins, styrene maleic anhydride resins, and the like. .

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

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, 300 to 1000 parts of an organic solvent and 10 to 100 parts of a dispersant are uniformly added per 100 parts of the pigment composition produced by the method of the present invention in terms of mass. The pigment dispersion can be obtained by stirring and dispersing so that The pigment dispersion is then subjected to a photopolymerization of 1 to 20 parts in total of the thermoplastic resin and the photocurable compound and 0.05 to 3 parts per part of the photocurable compound per part of the pigment composition of the present invention. A photocurable composition for forming a color filter blue pixel portion can be obtained by adding an initiator and, if necessary, further an organic solvent, and stirring and dispersing so as to be uniform.

As the developer, a 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. It is effective in forming. The excellent heat resistance of a pigment composition containing a suitable phthalocyanine derivative is exhibited in a method for producing a color filter in which baking is performed after such alkali washing.

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

The color filter uses, for example, a red pigment, a green pigment, and a photocurable composition of each color obtained by using the blue pigment composition of the present invention, and encloses a liquid crystal material between a pair of parallel transparent electrodes. The transparent electrode is divided into discontinuous fine sections, and each of the fine sections divided in a lattice pattern by the black matrix on the transparent electrode is red (R), green (G), or blue (B). Alternatively, a color filter coloring pixel portion selected from one color can be alternately provided in a pattern, or a color filter coloring pixel portion can be formed on a substrate and then a transparent electrode can be provided.

The color filter of the present invention may contain a copper phthalocyanine pigment, a zinc phthalocyanine pigment, and a resin having an epoxy group as essential components in the pixel portion.

In the preparation of the blue pigment dispersion and the photocurable composition, the case of using the blue pigment composition of the present invention has been described in detail as an example. However, a blue pigment dispersion containing a copper phthalocyanine pigment and a zinc phthalocyanine pigment are used. And a blue pigment dispersion containing the mixture, to prepare a photocurable composition therefrom, and then to form a color filter blue pixel portion, a photocurable composition containing a copper phthalocyanine pigment, and a zinc phthalocyanine pigment You may form a color filter blue pixel part from the photocurable composition containing this.

However, a method of obtaining a pigment dispersion containing a copper phthalocyanine pigment and a zinc phthalocyanine pigment in advance through the blue pigment composition of the present invention, preparing a photocurable composition therefrom, and then forming a color filter However, a color filter having the highest luminance of the liquid crystal display screen can be obtained.

The pigment composition for a color filter of the present invention can display a liquid crystal screen with high brightness and high contrast, and in addition to color filter applications, paint, plastic (resin molded product), printing ink, rubber, leather, textile printing It can also be applied to coloring of electrostatic charge image developing toner, ink jet recording ink, thermal transfer ink and the like.

The liquid crystal display device of the present invention has the above-described color filter of the present invention.

Examples of the liquid crystal display device of the present invention include a liquid crystal display device having a color filter, a counter substrate having a TFT array substrate and the like, and a liquid crystal layer formed between the color filter and the counter substrate. Note that the liquid crystal display device of the present invention is not limited to the above-described configuration, and can be a configuration generally known as a liquid crystal display device using a color filter.

The driving method of the liquid crystal display device of the present invention is not particularly limited, and a driving method generally used for a liquid crystal display device can be employed. Examples of such a drive method include a TN method, an IPS method, an OCB method, and an MVA method. In the present invention, any of these methods can be preferably used.

Further, the counter substrate can be appropriately selected and used according to the driving method of the liquid crystal display device of the present invention.

Furthermore, as the liquid crystal constituting the liquid crystal layer, various liquid crystals having different dielectric anisotropy and mixtures thereof can be used according to the driving method of the liquid crystal display device of the present invention.

As a method for forming a liquid crystal layer, a method generally used as a method for producing a liquid crystal cell can be used, and examples thereof include a vacuum injection method and a liquid crystal dropping method.

In the vacuum injection method, for example, a liquid crystal cell is prepared in advance using a color filter and a counter substrate, and the liquid crystal is heated to obtain an isotropic liquid, and the liquid crystal is applied to the liquid crystal cell using the capillary effect. The liquid crystal layer can be formed by injecting in this state and sealing with an adhesive. Thereafter, the sealed liquid crystal can be aligned by slowly cooling the liquid crystal cell to room temperature.

In the liquid crystal dropping method, for example, a sealant is applied to the periphery of the color filter, the color filter is heated to a temperature at which the liquid crystal becomes isotropic, and the liquid crystal is dropped in an isotropic liquid state using a dispenser or the like. In addition, the liquid crystal layer can be formed by overlapping the color filter and the counter substrate under reduced pressure and bonding them with a sealant. Thereafter, the sealed liquid crystal can be aligned by slowly cooling the liquid crystal cell to room temperature.

Hereinafter, the present invention will be described in more detail using examples and comparative examples. In the following examples and comparative examples, “part” and “%” are both based on mass.

[Synthesis Example 1]
A four-necked flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube was charged with 1540 parts of propylene glycol monomethyl ether acetate, heated to 110 ° C. under a nitrogen stream, 597 parts of methyl methacrylate, and n-butyl. A mixed solution consisting of 261 parts of methacrylate, 142 parts of glycidyl methacrylate and 18 parts of t-butylperoxy-2-ethylhexanoate was added dropwise over 4 hours. After completion of dropping, the reaction was carried out at 110 ° C. for 7 hours. After completion of the reaction, the mixture was heated under reduced pressure to distill off propylene glycol monomethyl ether acetate to obtain a resin having an epoxy group having an epoxy equivalent of 500 and a weight average molecular weight of 15,000.

[Production Example 1]
In a 1000 ml four-necked flask, 51.2 g of phthalodinitrile, 30.4 g of 1,8-diazabicyclo [5.4.0] -7-undecene (DBU), and 200 ml of n-pentanol were charged under a nitrogen atmosphere. Heated and stirred. At 70 to 75 ° C., 13.62 g of zinc chloride was added thereto, and then heated at 95 to 100 ° C. for 5 hours. The precipitate was collected by filtration, washed with an organic solvent, dried and purified to obtain crude zinc phthalocyanine.

100 parts of the obtained crude zinc phthalocyanine, 1000 parts of crushed sodium chloride, and 160 parts of diethylene glycol were charged into a double-arm kneader and kneaded at 80 to 90 ° C. for 8 hours. The obtained contents are washed with a large excess of water, filtered, washed with water until the specific conductivity of the filtrate is equal to or less than the specific conductivity of raw water plus 20 μS / cm, dried and crushed, and the average particle size of primary particles A zinc phthalocyanine pigment of 200 nm or less was obtained.
[Production Example 2]

85 parts of FASTOGEN BLUE AE-8 (ε-type copper phthalocyanine pigment manufactured by DIC Corporation), 5 parts of zinc phthalocyanine pigment of Production Example 1, 10 parts of resin having an epoxy group of Synthesis Example 1, 1000 parts of crushed sodium chloride, and diethylene glycol 160 parts were charged into a double-arm kneader and kneaded at 80 to 90 ° C. for 8 hours.
The obtained contents were washed with a large excess of water, filtered, and washed with water until the specific conductivity of the filtrate was equal to or less than the specific conductivity of raw water + 20 μS / cm, whereby a wet cake of ε-type copper phthalocyanine pigment composition was obtained. Obtained. The obtained wet cake was transferred to a beaker, 3000 parts of a 2% hydrochloric acid aqueous solution was added, dispersed by stirring to form a slurry, stirred at 70 ° C. for 1 hour, filtered and washed with water to obtain a wet cake.
The obtained wet cake was transferred to a beaker, 3000 parts of a 0.5% aqueous sodium hydroxide solution was added, and the mixture was stirred and dispersed to form a slurry. After stirring at 70 ° C. for 2 hours, the pH was returned to 9. Subsequently, an aqueous sodium hydroxide solution of 5 parts of copper phthalocyanine sulfonic acid derivative having an average number of substituents of 0.8 is added to the pigment slurry, and after stirring for 1 hour, hydrochloric acid is added to return the pH of the slurry to 7, It was deposited on the surface. After being kept for 1 hour, it was filtered, washed with warm water, dried and pulverized to obtain a pigment composition having an average primary particle diameter of 100 nm or less.
[Production Example 3]

A pigment composition was obtained in the same manner as in Production Example 2, except that 85 parts of the copper phthalocyanine pigment of Production Example 2 was replaced with 80 parts of the copper phthalocyanine pigment and 5 parts of the copper phthalocyanine phthalimidomethyl derivative having an average number of substituents of 1.4.
[Production Example 4]

A pigment composition was obtained in the same manner as in Production Example 2 except that 85 parts of the copper phthalocyanine pigment and 5 parts of the zinc phthalocyanine pigment of Production Example 2 were replaced with 80 parts of the copper phthalocyanine pigment and 10 parts of the zinc phthalocyanine pigment.
[Production Example 5]

A pigment composition was obtained in the same manner as in Production Example 2 except that 85 parts of the copper phthalocyanine pigment and 5 parts of the zinc phthalocyanine pigment of Production Example 2 were replaced with 90 parts of the copper phthalocyanine pigment.
[Production Example 6]

Pigment composition as in Production Example 2 except that 85 parts of the copper phthalocyanine pigment of Production Example 2 and 5 parts of the zinc phthalocyanine pigment were replaced with 85 parts of the copper phthalocyanine pigment and 5 parts of the copper phthalocyanine phthalimidomethyl derivative having an average number of substituents of 1.4. I got a thing.
[Production Example 7]

Manufactured except that 85 parts of copper phthalocyanine pigment, 5 parts of zinc phthalocyanine pigment of Production Example 2 and 10 parts of resin having an epoxy group of Synthesis Example 1 were replaced with 94.4 parts of copper phthalocyanine pigment and 5.6 parts of zinc phthalocyanine pigment. In the same manner as in Example 2, a pigment composition was obtained.
[Production Example 8]

A pigment composition was obtained in the same manner as in Production Example 2 except that 85 parts of the copper phthalocyanine pigment and 5 parts of the zinc phthalocyanine pigment in Production Example 2 were replaced with 87.5 parts of the copper phthalocyanine pigment and 2.5 parts of the zinc phthalocyanine pigment. .
[Production Example 9]

85 parts of the copper phthalocyanine pigment of Production Example 2 and 5 parts of the zinc phthalocyanine pigment are replaced with 87.5 parts of the copper phthalocyanine pigment and 2.5 parts of the zinc phthalocyanine pigment, and 10 parts of the epoxy group-containing resin of Synthesis Example 1 is also added to EPICLON 1055 ( A pigment composition was obtained in the same manner as in Production Example 2 except that 10 parts by DIC Corporation, bisphenol A type epoxy resin, epoxy equivalent 470, weight average molecular weight 2000) were used.
[Example 1]

10 parts of the pigment composition obtained in Production Example 2 is put in a polyvin, 55 parts of propylene glycol monomethyl ether acetate, 7.0 parts of BYK (trade name) LPN21116 (manufactured by Big Chemie Co., Ltd.), 0.3-0.4 mmφ Sepul beads were added and dispersed for 4 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.) to obtain a pigment dispersion. 75.00 parts of this pigment dispersion, 5.50 parts of polyester acrylate resin (Aronix (trade name) M7100, manufactured by Toa Gosei Chemical Co., Ltd.), dipentaerythrate hexaacrylate (KAYARAD (trade name) DPHA, Nippon Kayaku) 5.00 parts of Yakuhin Co., Ltd., 1.00 parts of benzophenone (KAYACURE (trade name) BP-100, Nippon Kayaku Co., Ltd.) and 13.5 parts of Euker Ester EFP were stirred with a dispersion stirrer. Filtration through a 0 μm filter gave a color resist. This color resist was applied to 50 mm × 50 mm, 1 mm thick glass using a spin coater so that the dry film thickness was 2 μm, and then pre-dried at 90 ° C. for 20 minutes to form a coating film. Next, pattern exposure with ultraviolet rays was performed through a photomask, and then the unexposed portion was washed in a 0.5% aqueous sodium carbonate solution and baked at 230 ° C. for 60 minutes to obtain a glass substrate for evaluation.
[Example 2]

A glass substrate was prepared in the same manner as in Example 1 except that the pigment composition obtained in Production Example 3 was used.
[Example 3]

A glass substrate was prepared in the same manner as in Example 1 except that the pigment composition obtained in Production Example 4 was used.
[Example 4]

A glass substrate was prepared in the same manner as in Example 1 except that the pigment composition obtained in Production Example 8 was used.
[Example 5]

A glass substrate was prepared in the same manner as in Example 1 except that the pigment composition obtained in Production Example 9 was used.
[Comparative Example 1]

A glass substrate was prepared in the same manner as in Example 1 except that the pigment composition obtained in Production Example 5 was used.
[Comparative Example 2]

A glass substrate was prepared in the same manner as in Example 1 except that the pigment composition obtained in Production Example 6 was used.
[Comparative Example 3]

A glass substrate was prepared in the same manner as in Example 1 except that the pigment composition obtained in Production Example 7 was used.

The contrast value and the luminance were measured for the glass substrate obtained above based on the following evaluation method. In particular, Table 1 shows the results of the luminance change before and after the post-bake and the contrast value after the post-bake.

(Evaluation methods)
<Contrast>
The said glass substrate was installed between two polarizing plates, the light source was installed in one side, and the color luminance meter was installed in the other side, and the brightness | luminance was measured. It was calculated from the ratio of luminance (transmitted light intensity) between when the polarization axis was parallel and when it was vertical. A higher contrast value was evaluated as better.
<Luminance>
The glass substrate was measured for luminance Y value in a C light source by MCPD-3000 manufactured by Otsuka Electronics Co., Ltd. Moreover, the brightness | luminance after heating the glass substrate for evaluation at 230 degreeC for 1 hour (post-baking) was measured similarly.

Table 1

As can be seen from the comparison between Example 1 and Comparative Example 1 in Table 1 above, by including the zinc phthalocyanine pigment, the luminance change before and after the post-baking and the contrast after the post-baking can be achieved at a high level. In Comparative Example 2 in which a copper phthalocyanine phthalimidomethyl derivative was used instead of the zinc phthalocyanine pigment, the contrast after post-baking was high, but the luminance change before and after post-baking was large, and both were not compatible. On the other hand, in Comparative Example 3 not including a resin having an epoxy group, the luminance change before and after the post-baking was good, but the contrast after the post-baking was low, and this was not compatible.

From this, it was clarified that both brightness and contrast can be achieved at a high level only when both zinc phthalocyanine pigment and epoxy group-containing resin are included.

The pigment composition for a color filter of the present invention has a high heat resistance, and can provide a higher brightness and a higher contrast, so that a color filter capable of brighter liquid crystal display can be provided.

Claims (6)

1. A color filter pigment composition comprising a copper phthalocyanine pigment, a zinc phthalocyanine pigment, and a resin having an epoxy group.
2. Of 100 parts of the pigment composition in terms of mass, the content of copper phthalocyanine pigment is 65 to 94.9 parts, the content of zinc phthalocyanine pigment is 0.1 to 15 parts, and the content of resin having an epoxy group is 5 The pigment composition for a color filter according to claim 1, wherein the amount is from 20 parts to 20 parts.
3. The color filter pigment composition according to claim 1, wherein the copper phthalocyanine is ε-type copper phthalocyanine.
4. 4. The color filter pigment composition according to claim 1, wherein the epoxy group-containing resin has an epoxy equivalent of 200 to 2000 and a weight average molecular weight of 500 to 20000.
5. The method for producing a pigment composition for a color filter according to any one of claims 1 to 4, comprising a step of kneading a mixture of a copper phthalocyanine pigment, a zinc phthalocyanine pigment and a resin having an epoxy group together with a water-soluble inorganic salt and a water-soluble organic solvent.
6. A color filter comprising the pigment composition for a color filter according to any one of claims 1 to 4 or the pigment composition for a color filter obtained by the production method according to claim 5.