JP2017088703A - Pigment composition for color filters, and color filters - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color filter having an excellent contrast and a pigment composition suitable for obtaining the color filter.SOLUTION: A pigment composition for color filters comprises a diketopyrrolopyrrole pigment, and a triazine compound represented by formula (I).SELECTED DRAWING: None

Description

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

  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, red organic pigments for forming a red pixel portion are generally diketopyrrolopyrrole pigments (CI Pigment Red 254) and diaminodianthraquinone pigments (CI Pigment Red 177). In addition, a condensed azo pigment (CI Pigment Red 242) is used, and a yellow organic pigment isoindoline pigment (CI Pigment Yellow 139), a nickel azo pigment is used for color matching as necessary. (CI Pigment Yellow 150) 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 (higher contrast), or the same display screen. There is a demand for making the image brighter (higher brightness). In order to meet such requirements, powdered organic pigments that have been refined to have an average primary particle size of 100 nm or less are frequently used. Further, since the aggregation of the particles is likely to occur due to the refinement of the pigment particles, it is indispensable to maintain the dispersibility in order to satisfy the demand for high contrast and high brightness.

  Patent Document 1 uses a pigment composition produced by wet-grinding a dianthraquinone pigment or a diketopyrrolopyrrole pigment in the presence of a compound having a specific triazine structure bonded to an azo pigment skeleton, It is disclosed that a color filter with good brightness can be produced. Moreover, the following is mentioned as literature which made it a subject to obtain the color filter which has a high contrast ratio. Patent Document 2 discloses a red coloring composition for a color filter using a diketopyrrolopyrrole red pigment and a pigment derivative in which a specific triazine group is bonded to a quinophthalone pigment residue. Patent Document 3 discloses a green coloring composition for a color filter using a zinc halide phthalocyanine pigment and a dye derivative in which a specific triazine group is bonded to a benzimidazolone pigment residue. In any of these patent documents, a compound in which a pigment residue and a specific triazine group are bonded is used.

  As described above, various studies have been conducted to achieve higher contrast, but there has always been a demand for pigment compositions that can achieve higher contrast in order to create higher-performance color filters. Yes.

JP 2007-314681 A JP 2012-173319 A JP 2010-1000078 A

  The problem to be solved by the present invention is to provide a color filter excellent in contrast, a pigment composition suitable for obtaining the same, and a method for producing the same.

  The inventors of the present invention have made extensive studies on a color filter excellent in contrast, an organic pigment composition suitable for obtaining the color filter, and a method for producing the same, and are described in the diketopyrrolopyrrole pigment and the patent document. When a pigment composition containing a specific triazine compound that has not been used is used in a color filter, it has been found that a color filter with excellent contrast can be obtained, and the present invention has been completed.

That is, the present invention relates to the following items 1 to 4.
Item 1. Diketopyrrolopyrrole pigment (α) and the following formula (I)

[Wherein, X each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, a cyano group, a trifluoromethyl group, a nitro _group, C 1 -C ₈ alkyl _group, C 3 -C ₈ cycloalkyl A triazine compound (β) represented by a group, a C _{2 to} C ₈ alkenyl group, a C _{1 to} C ₈ alkoxy group, a phenyl group, or a benzyl group].

Item 2. The diketopyrrolopyrrole pigment (α) is represented by the following formula (II)

（式中、Ｒは、塩素原子、臭素原子又はフェニル基である）で表されるものである請求項１に記載のカラーフィルタ用顔料組成物。

The pigment composition for a color filter according to claim 1, wherein R is a chlorine atom, a bromine atom or a phenyl group.

Item 3. Item 3. The color filter pigment according to Item 1 or 2, which contains 0.1 to 10 parts of the triazine compound (β) per 100 parts of the diketopyrrolopyrrole pigment (α) in terms of mass. Composition.

Item 4. The color filter containing the pigment composition according to any one of Items 1 to 3 in a red pixel portion.

  When the pigment composition for a color filter of the present invention contains a specific triazine compound described later, a color filter having excellent contrast can be obtained when the pigment composition is used for a color filter.

  The pigment composition of the present invention comprises a diketopyrrolopyrrole pigment (α) and the following formula (I):

[Wherein, X each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, a cyano group, a trifluoromethyl group, a nitro _group, C 1 -C ₈ alkyl _group, C 3 -C ₈ cycloalkyl A triazine compound (β) represented by a group, a C ₂ -C ₈ alkenyl group, a C ₁ -C ₈ alkoxy group, a phenyl group, or a benzyl group]. Hereinafter, the triazine compound (β) represented by the formula (I) is abbreviated as a triazine compound (β).

  The diketopyrrolopyrrole pigment (α) is a red to orange pigment, and has excellent light resistance and heat resistance. Examples of the diketopyrrolopyrrole pigment (α) include C.I. I. Pigment red 254, C.I. I. Pigment red 255, C.I. I. Pigment red 264, C.I. I. Pigment red 270, C.I. I. Pigment red 272, C.I. I. And red pigments such as CI Pigment Red 283, 3, 6-bis (4-bromophenyl) diketopyrrolopyrrole. In addition, C.I. I. Pigment orange 71, C.I. I. Pigment orange 73, C.I. I. And orange pigments such as CI Pigment Orange 81. In the present invention, among these, a red pigment is used, and a suitable red pigment is represented by the following formula (II):

[Wherein R is a chlorine atom, a bromine atom or a phenyl group]. I. Pigment Red 254 or 3,6-bis (4-bromophenyl) diketopyrrolopyrrole.

  The triazine compound (β) has the following formula (I)

[Wherein, X each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, a cyano group, a trifluoromethyl group, a nitro _group, C 1 -C ₈ alkyl _group, C 3 -C ₈ cycloalkyl _group, C 2 -C ₈ alkenyl _group, C 1 -C ₈ alkoxy group, a compound represented by a phenyl group or a benzyl group], the following formula is a preferred embodiment (I-i)

[X is as described above].

In the above formulas (I) and (I-i), X is a chlorine atom, a bromine _atom, C 1 -C ₈ alkyl _group, C 1 -C ₈ alkoxy group is preferably a phenyl group, among others C and more preferably ₁ -C ₈ alkoxy group. Among C ₁ -C ₈ alkoxy groups, more preferred are a methoxy group and an ethoxy group.

  The triazine compound (β) used in the present invention is, for example, dichloromethane, the following formula (γ)

In the formula, R represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, a cyano group, a trifluoromethyl group, a nitro _group, C 1 -C ₈ alkyl _group, C 3 -C ₈ cycloalkyl group, _{C 2} -C ₈ alkenyl group, C ₁ -C ₈ alkoxy group, dissolved benzonitrile represented by a phenyl group or a benzyl group] was added dropwise trifluoromethanesulfonic acid, it can be obtained by reacting. The reaction time can be, for example, 24 hours to 72 hours, and the reaction temperature can be room temperature. Next, this mixed solution is neutralized by adding a 10% by weight aqueous sodium hydroxide solution, filtered, washed with dichloromethane and methanol, and subjected to column purification as necessary to obtain the desired triazine compound (β). Can do.

  The pigment composition of the present invention is prepared by containing the diketopyrrolopyrrole pigment (α) and the triazine compound (β) so that the latter is 0.1 to 10 parts per 100 parts of the former in terms of mass. can do.

  Since the pigment composition of the present invention is used for 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 diameter of 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, 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.

  In the pigment composition of the present invention, the above-mentioned diketopyrrolopyrrole pigment (α) may be composed of particles that are not coated with a polymer, but a red pigment dispersion such as a color filter paste described later, In order to ensure better dispersibility in a photocurable composition such as a resist, it is preferable to be 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 diketopyrrolopyrrole pigment (α). Examples of the polymer at this time include, for example, styrene- (meth) acrylic acid copolymer, styrene-butyl (meth) acrylate- (meth) acrylic acid copolymer, lauryl (meth) acrylate- (meth) acrylic acid. Copolymer, Styrene- (meth) acrylate lauryl- (meth) acrylic acid copolymer, (meth) acrylic acid benzyl- (meth) acrylic acid copolymer, (meth) acrylic acid benzyl- (meth) acrylic acid Examples thereof include a methyl copolymer and benzyl (meth) acrylate-methyl (meth) acrylate- (meth) acrylic acid copolymer. 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.

  The diketopyrrolopyrrole red pigment coated with a benzyl (meth) acrylate- (meth) acrylic acid copolymer was used as the diketopyrrolopyrrole pigment (α) in the pigment composition suitable for the present invention. Is.

In the pigment composition for a color filter of the present invention, other red organic pigments or red organic pigment derivatives may be used in combination for purposes such as toning. For example, 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 CI Pigment Red 209.
In addition, red organic pigment derivatives include sulfonic acid derivatives of diketopyrrolopyrrole pigments, phthalimide alkylated derivatives of diketopyrrolopyrrole pigments, sulfonic acid derivatives of quinacridone red pigments, and phthalimide alkylation of quinacridone red pigments. Derivatives and the like.

Diketopyrrolopyrrole pigment (α) and triazine compound (β) and triazine compound (β) in the mixture of other red organic pigment or red organic pigment derivative added as necessary ), The greater the total ratio, the higher the effect of the present invention. Of the other red organic pigments and red organic pigment derivatives, if the red organic pigment is taken as an example, the total amount of diketopyrrolopyrrole pigment (α) and triazine compound (β) per 100 parts in terms of mass The red organic pigment can be contained in an amount of 1 to 200 parts.
In the case of phthalimidoalkylated quinacridone, 1 to 100 parts can be contained per 100 parts in total of the diketopyrrolopyrrole pigment (α) and the triazine compound (β), preferably 1 to 20 parts, more preferably May contain 10-20 parts.

  These other red organic pigments and red organic pigment derivatives may be similarly coated with the above-described polymer.

  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 to obtain a highly transparent colored coating film.

  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 does not decrease and 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 recently been required. 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.

  Next, the method for producing the pigment composition of the present invention will be described in detail.

  The pigment composition of the present invention includes, for example, a diketopyrrolopyrrole pigment (α), a triazine compound (β), and, if necessary, other red organic pigments and red organic pigment derivatives in the mass ratio described above. Thus, it can be produced by mixing in any order. In the pigment composition of the present invention, the diketopyrrolopyrrole pigment (α) and the triazine compound (β) may be sufficiently mixed in advance, and another red organic pigment may be added thereto. If necessary, diketopyrrolopyrrole pigment (α), triazine compound (β) and other red organic pigments or red organic pigment derivatives may be ball milled or atomized before mixing, or after mixing. It can also be ground by a known and conventional means such as a lighter so as to obtain the above-mentioned preferred average particle diameter of primary particles.

  However, there is a method for easily producing a pigment composition that exhibits a higher improvement effect and that has a suitable average particle size of primary particles as described above. Examples thereof include a method of wet-grinding a diketopyrrolopyrrole pigment (α) and a triazine compound (β). In particular, a solvent salt milling method is suitable, that is, a method for producing a color filter pigment composition in which a diketopyrrolopyrrole pigment (α) and a triazine compound (β) are solvent salt milled.

  The red organic pigment composition of the present invention comprises a step of dissolving the diketopyrrolopyrrole pigment (α) obtained as described above in a basic solvent (referred to as the first step), and the mixed solution is acidic to medium. Step to obtain fine and uniform pigment particles (second step), pigment particles obtained in the second step, further pigment derivatives, and acrylic copolymer if necessary By grinding, it can be produced by three steps of a particle control step (referred to as a third step). By carrying out like this, the average primary particle diameter of a pigment can be 20-50 nm. Specifically, in the first step, the pigment is dissolved as a metal salt in an aprotic polar solvent in which an alcoholate is previously dissolved. The second step is a step of obtaining fine and uniform pigment particles by taking out the mixed solution in which the pigment prepared in the first step is dissolved into an acidic to neutral solution. In the third step, a fine secondary particle organic pigment composition is obtained by mechanically grinding a mixture of the pigment particles obtained in the second step, and further a pigment derivative, an acrylic copolymer, an inorganic salt, and an organic solvent. It is a process to obtain. Hereinafter, the first step, the second step, and the third step will be described in more detail.

[First step]
As described above, the first step is a step of dissolving the diketopyrrolopyrrole pigment (α) uniformly in a basic solvent at the molecular level. As dissolution conditions, basicity, temperature, and stirring state are important.

  As the solvent used in the first step, an aprotic polar solvent is generally used. The aprotic polar solvent is a solvent having excellent solubility that is miscible with water in a free ratio and dissolves many organic compounds and inorganic salts. Examples include ethers (diethyl ether, tetrahydrofuran, etc.), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), hexamethylphosphoric triamide (HMPA), N-methyl-2-pyrrolidone (NMP), and the like. In the present invention, dimethyl sulfoxide is preferable from the viewpoint of high solubility of a condensed polycyclic pigment such as a diketopyrrolopyrrole pigment (α).

  Lithium, potassium, and sodium can be used as the alkali metal. However, alcoholates are generally used because those that are readily soluble in the aprotic polar solvent are preferred. Sodium methoxide, sodium ethoxide, potassium t-butoxide and the like are commercially available, and sodium methoxide is preferred in the present invention in consideration of cost and operability.

  The alkali metal may be dissolved in the solvent at any ratio as long as the diketopyrrolopyrrole pigment (α) is dissolved, but 0.2 to 10 parts with respect to 100 parts of the mixed solution in consideration of productivity. Is preferable, and 0.5 to 5 parts is more preferable.

  The amount of the solvent for the pigment is preferably large in consideration of solubility, but is preferably 5 to 50 parts, more preferably 10 to 40 parts relative to 1 part of the pigment in consideration of productivity.

  The temperature at the time of dissolution may be any temperature as long as the pigment can be dissolved in the solvent, but in order to further improve the solubility, it is preferable to set the dissolution temperature to a temperature higher than normal temperature. In this invention, 20-120 degreeC is preferable and 40-110 degreeC is more preferable.

[Second step]
In this step, the mixed solution in which the pigment prepared in the first step is dissolved is taken out into an acidic to neutral solution to precipitate fine and uniform pigment particles.

  As a method of taking out the solution into an acidic to neutral solution, any publicly known method can be used. The acid-to-neutral solution prepared in advance is made into a turbulent state with a stirring device or the like, and the solution obtained in the first step is taken out. In the case of laminar flow, since the dilution rate is slow, the diffusion effect of the heat of neutralization is low, and there is a possibility of crystal growth. The take-out speed of the solution may be arbitrary, but is appropriately adjusted in order to obtain fine particles depending on the speed of the water flow and the state of the water flow. The solution may be taken out directly into an acidic to neutral solution, or there is a method of suppressing crystal growth due to contact between a small amount of solution and an acidic to neutral solution with an apparatus such as an ejector.

  Although depending on the take-off speed and take-out method, it is preferable to cool the precipitation tank in order to prevent crystal growth due to the precipitation temperature. It is preferable to cool by water cooling, ice cooling, or cooling with a coolant and control the deposition temperature to 40 ° C. or lower, and in the present invention, lower 20 ° C. or lower is more preferable.

  The more the acidic to neutral solution is, the higher the diffusion rate, with respect to the solution in which the pigment is dissolved. However, in consideration of productivity and operability, 1 to 10 parts per 1 part of the mixed solution is preferable. preferable.

  The obtained slurry is filtered, washed, dried and pulverized to obtain fine and uniform pigment particles.

[Third step]
To the organic pigment composition obtained in the second step, a triazine compound (β), a pigment derivative and, if necessary, an acrylic copolymer are added, and fine primary particles that are the final purpose are obtained by mechanical grinding. This is a process for producing an organic pigment composition.

  As a typical method for coating the diketopyrrolopyrrole pigment (α) with the polymer, 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 a polymer to the pigment composition of the present invention which is not coated with a polymer obtained in advance, a method of adding a polymer emulsion, a method of kneading and grinding with a polymer, etc. is there. In the solvent salt milling treatment, in order to sufficiently control the crystal of the diketopyrrolopyrrole pigment (α), it is preferable to use an excellent crystal growth inhibiting action of the derivative, and the polymer is a diketopyrrolopyrrole pigment ( It is preferable not to inhibit the pigment derivative from adsorbing to α). After the completion of crystal control, these diketopyrrolopyrrole pigments (α) may be coated with a polymer.

  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. As kneading means at this time, for example, a kneader, a mix muller, Trimix (registered trademark) manufactured by Inoue Seisakusho, which is a planetary mixer described in JP-A-2007-100008, or JP-A-4-122778. The continuous twin-screw extruder described in No. 2006, Miracle KCK manufactured by Asada Tekko Co., Ltd., which is a continuous single-screw kneader described in JP-A-2006-306996, and the like can be used. Of these, kneading with a batch kneader is preferred. More specifically, examples of the kneader include a salt milling kneader.

  As the inorganic salt, a water-soluble inorganic salt can be suitably used. For example, it is preferable to use an inorganic salt such as sodium chloride, potassium chloride, or 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 organic pigment composition and the pigment derivative as essential components in terms of mass. 7 to 30 parts, particularly 10 to 30 parts are preferred.

  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 like.

  Although the usage-amount of an organic solvent is not specifically limited, 0.01-5 parts is preferable per 1 part in total of the mixture containing a red pigment and a derivative as an essential component in conversion of mass.

  In the production method of the present invention, when performing the solvent salt milling treatment, other red organic pigments or red organic pigment derivatives can be contained as necessary for the purpose of adjusting the intended hue.

  In the solvent salt milling process, the inorganic salt and the organic solvent as described above are charged in the initial preparation stage, and the mixture containing the pigment composition and the pigment derivative as essential components is added as the necessary primary components. Grinding may be performed until the average particle size of the particles is reached, or only a part of the required amount is charged and grinding is started, and the remaining amount of inorganic salt and / or organic solvent is divided or divided in the middle. Grinding may be performed as in

  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. be able to.

  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.

In addition, as this washing | cleaning method, both water washing and hot water washing can be employ | adopted. 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. The specific conductivity here refers to the difference in the conductivity of the filtrate with respect to the conductivity of water. Specifically, the method for measuring the specific conductivity of the pigment composition is determined as follows.
1. Weigh 5.00 g of pigment correctly in a 500 mL hard beaker, add 200 mL of ion-exchanged water (conductivity 5 μS / cm or less, pH = 7.0 ± 1.0) in small portions, and add 5 mL of reagent primary methanol. After wetting well, add the whole amount and boil for 5 minutes.
2. This was cooled to room temperature, transferred to a 250 mL graduated cylinder, further added with the above ion-exchanged water to 250 mL, and stirred well to make a filter paper No. 1 manufactured by Advantech. Filter at 5C.
3. Discard the first approximately 50 mL of the filtrate, and weigh out 100 mL from the remainder with a graduated cylinder and transfer to an evaporating dish of known mass. Rinse the filtrate adhering to the graduated cylinder into the evaporating dish with a small amount of ion exchange water.
4). After measuring the specific conductivity of ion-exchanged water using a conductivity meter (CM-30V, etc., manufactured by Toa DKK Co., Ltd.), the filtrate obtained by measuring 100 mL with a graduated cylinder in 3 above was used for the same conductivity meter. Measured using, and calculated by correcting the measured value according to the following equation.
Specific conductivity of pigment = specific conductivity of filtrate−specific conductivity of ion-exchanged water used

  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 preferably has an aspect ratio closer 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 a color filter pigment dispersion and a composition of a photocurable compound and / or a synthetic resin, which will be described later, and the coating properties on a transparent substrate for forming a color filter red pixel portion are the same. This is not preferable in that all of the reduction and 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.

  For each color of red, green, and blue, a photocurable composition to be described later is prepared, and the above-described operation is repeated to manufacture a color filter having red, green, and blue colored pixel portions at predetermined positions. be able to. 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 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 ester solvents such as mixtures of 48:52 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 Bifunctional monomers such as acrylates, trimethylolpropane triacrylate, pentaerythritol triacrylate, tris (2-hydroxyethyl) isocyanate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, etc. Polyfunctional monomers having a relatively large molecular weight such as polyester acrylate, polyurethane acrylate, and polyether acrylate.

  Examples of the photopolymerization initiator include acetophenone, benzophenone, benzyldimethyl ketal, 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 described above, the pigment composition of the present invention has a uniform amount of 300 to 1,000 parts of organic solvent and 0 to 100 parts of dispersant per 100 parts in terms of mass. The pigment dispersion can be obtained by stirring and dispersing as described above. 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 size 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 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 for forming the 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 uses a blue organic pigment composition, a green organic pigment composition, and a photocurable composition of each color obtained using the organic pigment composition of the present invention that is red, and a pair of parallel transparent electrodes A liquid crystal material is sealed in between, and the transparent electrode is divided into discontinuous fine sections, and red (R) and green (G) are divided into the fine sections divided in a lattice form by the black matrix on the transparent electrode. And a method of providing color filter coloring pixel portions selected from any one of blue and blue (B) alternately in a pattern, or forming a color filter coloring pixel portion on a substrate and then providing a transparent electrode. Can be obtained at

  As a matter of course, the color filter of the present invention further includes an anthraquinone red pigment in the red pixel portion, a nickel azo complex pigment in the green pixel portion, a dioxazine billet pigment in the blue pixel portion, if necessary. A liquid crystal color filter may be included.

  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, “part” and “%” are based on mass unless otherwise specified. Hereinafter, the measurement method used in this example is shown.

(1) Molecular weight measurement About 5 mg of a sample was dispersed in 1 ml of THF to prepare a solution, and GC / TOFMS JMS-T100GC, manufactured by JEOL Ltd. was used.

(2) Composition analysis The structure of the compound was determined using FT-NMR AVANCE-400, manufactured by Bruker BioSpin Co., Ltd. (solvent d ₆ -DMSO used).

[Production Example 1]
In 36.40 parts of dichloromethane, 5.20 parts of 4-methoxybenzonitrile was dissolved, and 11.00 parts of trifluoromethanesulfonic acid was slowly added dropwise, followed by stirring at room temperature for 48 hours. Next, a 10 wt% aqueous sodium hydroxide solution was added to the mixed solution, and after filtration, the mixture was washed with dichloromethane and methanol to obtain 4.10 parts of a triazine compound (β-1).
m / z = 399
¹ H NMR (300 MHz, d ₆ -DMSO) δ: 3.58 (9H), 6.83 (6H), 8.00 (6H)

[Production Example 2]
(First step)
C. I. Pigment Red 254 47.00 parts was dissolved in a mixed solvent of 1550.00 parts of dimethyl sulfoxide and 52.00 parts of a 28 wt% methanol solution of sodium methoxide, stirred at 110 ° C for 30 minutes, and then allowed to cool to 90 ° C. A pigment solution was prepared.
(Second step)
The pigment solution obtained in the first step was dropped into ice water mixed with 230.000 parts of water and 270.00 parts of ice while stirring vigorously, and stirred for 1 hour after the completion of dropping. The obtained pigment suspension was filtered with Nutsche, filtered and washed with water until the pH of the filtrate was 8 or less, dried at 90 ° C. for 17 hours and pulverized to obtain 43.00 parts of a red pigment composition. .
(Third step)
29.40 parts of red pigment composition obtained in the second step, 0.60 part of triazine compound (β-1), 6.00 parts of phthalimidomethylated dichloroquinacridone, benzyl (meth) acrylate- (meth) acrylic acid 4.00 parts of a copolymer (non-volatile content), 400.00 parts of sodium chloride, and 70.00 parts of diethylene glycol were charged into a stainless steel 1 L kneader (manufactured by Yoshida Seisakusho) and kneaded at 80 ° C. for 8 hours. Next, this mixture was poured into 2 liters of warm water, stirred for 30 minutes to form a slurry, filtered through a Nutsche, and repeated washing with water until the water conductivity became approximately the same to remove sodium chloride and the solvent. Thereafter, the mixture was dried at 90 ° C. for 17 hours and pulverized to obtain 38.00 parts of a red pigment composition for color filters.

[Production Example 3]
A triazine compound (β-2) was obtained in the same manner as in Production Example 1 except that 5.20 parts of 4-methoxybenzonitrile was changed to 5.30 parts of 4-chlorobenzonitrile in Production Example 1.
m / z = 411
¹ H NMR (300 MHz, d ₆ -DMSO) δ: 7.23 (6H), 7.87 (6H)

[Production Example 4]
For color filters, in the same manner as in Production Example 2, except that 0.60 part of triazine compound (β-1) was changed to 0.60 part of triazine compound (β-2) in the third step of Production Example 2. A red pigment composition was obtained.

[Production Example 5]
A triazine compound (β-3) was obtained in the same manner as in Production Example 1 except that 5.20 parts of 4-methoxybenzonitrile was changed to 7.10 parts of 4-bromobenzonitrile in Production Example 1.
m / z = 545
¹ H NMR (300 MHz, d ₆ -DMSO) δ: 7.62 (6H), 7.66 (6H)

[Production Example 6]
For color filter, in the same manner as in Production Example 2, except that 0.60 part of triazine compound (β-1) was changed to 0.60 part of triazine compound (β-3) in the third step of Production Example 2 A red pigment composition was obtained.

[Production Example 7]
A triazine compound (β-4) was obtained in the same manner as in Production Example 1 except that 5.20 parts of 4-methoxybenzonitrile was changed to 4.60 parts of 4-methylbenzonitrile in Production Example 1.
m / z = 351
¹ H NMR (300 MHz, d ₆ -DMSO) δ: 2.34 (9H), 7.45 (6H), 8.60 (6H)

[Production Example 8]
For the color filter, in the same manner as in Production Example 2, except that 0.60 part of triazine compound (β-1) was changed to 0.60 part of triazine compound (β-4) in the third step of Production Example 2. A red pigment composition was obtained.

[Production Example 9]
A triazine compound (β-5) was obtained in the same manner as in Production Example 1 except that 5.20 parts of 4-methoxybenzonitrile was changed to 7.00 parts of 4-cyanobiphenyl in Production Example 1. m / z = 537
¹ H NMR (300 MHz, d ₆ -DMSO) δ: 7.25 (6H), 7.41 (3H), 7.49 (6H), 7.75 (6H), 7.96 (6H)

[Production Example 10]
For the color filter, the same method as in Production Example 2, except that 0.60 part of triazine compound (β-1) was changed to 0.60 part of triazine compound (β-5) in the third step of Production Example 2. A red pigment composition was obtained.

[Production Example 11]
In Production Example 1, except that 5.20 parts of 4-methoxybenzonitrile was changed to 1.70 parts of 4-methoxybenzonitrile, 1.80 parts of 4-chlorobenzonitrile, 2.40 parts of 4-bromobenzonitrile. In the same manner as in Production Example 1, a triazine compound (β-6) was obtained.
m / z = 451
¹ H NMR (300 MHz, d ₆ -DMSO) δ: 3.81 (3H), 7.03 (2H), 7.51 (2H), 7.62 (2H), 7.66 (2H), 8. 08 (2H), 8.25 (2H)

[Production Example 12]
For color filter, in the same manner as in Production Example 2, except that 0.60 part of triazine compound (β-1) is changed to 0.60 part of triazine compound (β-6) in the third step of Production Example 2. A red pigment composition was obtained.

[Production Example 13]
A triazine compound (β-7) was obtained in the same manner as in Production Example 1 except that 5.20 parts of 4-methoxybenzonitrile was changed to 5.20 parts of 3-methoxybenzonitrile in Production Example 1.
m / z = 399
¹ H NMR (300 MHz, d ₆ -DMSO) δ: 3.81 (9H), 7.04 (3H), 7.29 (3H), 7.44 (3H), 7.96 (3H)

[Production Example 14]
For the color filter, in the same manner as in Production Example 2, except that 0.60 part of triazine compound (β-1) was changed to 0.60 part of triazine compound (β-7) in the third step of Production Example 2. A red pigment composition was obtained.

[Production Example 15]
A triazine compound (β-8) was obtained in the same manner as in Production Example 1 except that 5.20 parts of 4-methoxybenzonitrile was changed to 5.30 parts of 3-chlorobenzonitrile in Production Example 1.
m / z = 411
¹ H NMR (300 MHz, d ₆ -DMSO) δ: 7.48 (6H), 7.97 (3H), 8.16 (3H)

[Production Example 16]
For the color filter, in the same manner as in Production Example 2, except that 0.60 part of triazine compound (β-1) was changed to 0.60 part of triazine compound (β-8) in the third step of Production Example 2. A red pigment composition was obtained.

[Production Example 17]
A triazine compound (β-9) was obtained in the same manner as in Production Example 1 except that 5.20 parts of 4-methoxybenzonitrile was changed to 7.10 parts of 3-bromobenzonitrile in Production Example 1.
m / z = 545
¹ H NMR (300 MHz, d ₆ -DMSO) δ: 7.43 (3H), 7.45 (3H), 7.67 (3H), 8.22 (3H)

[Production Example 18]
For color filter, in the same manner as in Production Example 2, except that 0.60 part of triazine compound (β-1) was changed to 0.60 part of triazine compound (β-9) in the third step of Production Example 2. A red pigment composition was obtained.

[Production Example 19]
To a 2 L glass flask equipped with a reflux tube, under a nitrogen atmosphere, 600 parts of tert-amyl alcohol, 110 parts of sodium tert-pentoxide, 100 parts of 4-bromobenzonitrile were added, and the mixture was heated to 100 ° C. with stirring. Mixed solution 1 was prepared.
Meanwhile, 100 parts of tert-amyl alcohol and 60 parts of diisopropyl succinate were added to a 500 ml glass flask and heated to 90 ° C. with stirring to prepare a mixed solution 2.
Thereafter, the mixed solution 1 heated to 100 ° C. was vigorously stirred, and the mixed solution 2 heated to 90 ° C. was slowly dropped into the mixed solution 1 at a constant rate over 30 minutes. After completion of the dropwise addition, heating and stirring were continued for 2 hours at 100 ° C. to obtain an alkali metal salt solution of a diketopyrrolopyrrole pigment. The obtained alkali metal salt solution of diketopyrrolopyrrole pigment was naturally cooled to 70 ° C., and then filtered with Nutsche. The filtrated product was poured into 1500 parts of water, stirred at 85 ° C. for 2 hours, filtered through Nutsche, and repeatedly washed with water until the pH of the filtrate was 8 or less. Then, it dried and grind | pulverized at 90 degreeC for 20 hours, and obtained 92 parts of compounds (P) of the following structure.

[Production Example 20]
In the first step of Production Example 2, C.I. I. A red pigment composition for a color filter was obtained in the same manner as in Production Example 2, except that 47.00 parts of Pigment Red 254 was changed to the compound (P) described in Production Example 19.

[Production Example 21]
In the first step of Production Example 2, C.I. I. Pigment Red 254 47.00 parts was changed to the compound (P) described in Preparation Example 19, and in the third step of Preparation Example 2, 0.60 part of the triazine compound (β-1) was added to the triazine compound ( A red pigment composition for a color filter was obtained in the same manner as in Production Example 2, except that it was changed to β-2).

[Production Example 22]
In the first step of Production Example 2, C.I. I. Pigment Red 254 47.00 parts was changed to the compound (P) described in Preparation Example 19, and in the third step of Preparation Example 2, 0.60 part of the triazine compound (β-1) was added to the triazine compound ( A red pigment composition for a color filter was obtained in the same manner as in Production Example 2, except that it was changed to β-3).

[Production Example 23]
In the first step of Production Example 2, C.I. I. Pigment Red 254 47.00 parts was changed to the compound (P) described in Preparation Example 19, and in the third step of Preparation Example 2, 0.60 part of the triazine compound (β-1) was added to the triazine compound ( A red pigment composition for a color filter was obtained in the same manner as in Production Example 2 except that β-4) was used.

[Production Example 24]
In the first step of Production Example 2, C.I. I. Pigment Red 254 47.00 parts was changed to the compound (P) described in Preparation Example 19, and in the third step of Preparation Example 2, 0.60 part of the triazine compound (β-1) was added to the triazine compound ( A red pigment composition for a color filter was obtained in the same manner as in Production Example 2, except that it was changed to β-5).

<Creation of color filter and contrast evaluation>

[Example 1]
18.00 parts of the red pigment composition for a color filter obtained in Production Example 2 is put in a polybin, 110.00 parts of propylene glycol monomethyl ether acetate, DISPERBYK (registered trademark) LPN21116 (manufactured by Big Chemie Co., Ltd.) 22.00 parts, 0.3-0.4 mmφ Sepul beads (manufactured by Saint-Gobain Co., Ltd.) were added and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.) to obtain a red pigment dispersion for color filters. 75.00 parts of this pigment dispersion, Aronix (registered trademark) M7100 (polyester acrylate resin, produced by Toa Gosei Chemical Co., Ltd., equivalent to a photocurable compound), 5.50 parts, KAYARAD (registered trademark) DPHA (Dipentaerythritol hexaacrylate, Nippon Kayaku Co., Ltd., equivalent to a photocurable compound.) 5.00 parts, KAYACURE (registered trademark) BP-100 (benzophenone, Nippon Kayaku Co., Ltd., Hikari It corresponds to a polymerization initiator.) 1.00 parts and 13.50 parts of Euker ester EEP were stirred with a dispersion stirrer and filtered with a filter having a pore size of 1.0 μm to obtain a color resist. This was coated on a 50 mm × 50 mm, 1 mm glass substrate by a color resist spin coater and pre-dried at 90 ° C. for 20 minutes to form a coating film. Next, after performing pattern exposure with ultraviolet rays through a photomask, the unexposed portion is washed in an aqueous solution of 0.5% sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) and baked at 230 ° C. for 60 minutes. The color filter was used.

[Example 2]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 4.

[Example 3]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 6.

[Example 4]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 8.

[Example 5]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 10.

[Example 6]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 12.

[Example 7]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 14.

[Example 8]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 16.

[Example 9]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 18.

[Example 10]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 20.

[Example 11]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 21.

[Example 12]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 22.

[Example 13]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 23.

[Example 14]
The same procedure as in Example 1 was performed except that the red pigment composition for color filter used in Example 1 was changed to the red pigment composition for color filter obtained in Production Example 24.

[Comparative Example 1]
In the third step of Production Example 2, the same method as in Production Example 2 except that the amount of the red pigment composition obtained in the second step is 30 parts and no triazine compound (β-1) is added. To obtain a red pigment composition for a color filter. Next, a color filter was produced in the same manner as in Example 1 using the obtained red pigment composition for a color filter.

[Comparative Example 2]
In the first step of Production Example 2, C.I. I. Pigment Red 254 was changed to Compound (P) described in Production Example 11, and in the third step of Production Example 2, the amount of the red pigment composition obtained in the second step was 30 parts, and the triazine compound was used. A red filter composition for a color filter was obtained in the same manner as in Production Example 2 except that (β-1) was not added. Next, a color filter was produced in the same manner as in Example 1 using the obtained red pigment composition for a color filter.

[Comparative Example 3]
In the third step of Production Example 2, the triazine compound (β-1) was changed to a triazine compound (Y) having a pigment residue obtained by referring to JP2010-1000078A (Patent Document 3). Except for the above, it was carried out in the same manner as in Production Example 2 to obtain a red pigment composition for a color filter. Next, a color filter was produced in the same manner as in Example 1 using the obtained red pigment composition for a color filter.

Contrast values after baking at 230 ° C. (after post-baking) of the color filters prepared in the above Examples and Comparative Examples were measured and calculated according to the following evaluation method. The results are shown in Table 1.
[Evaluation method]
<Contrast measurement method>
The color filter red pixel portion obtained in the following examples and comparative examples was measured using a contrast tester (manufactured by Aisaka Electric Co., Ltd., device name: CT-1). This apparatus has a place where a color filter red pixel portion is installed between two polarizing plates, and a light source is installed on one side of the polarizing plate, and a color luminance meter is installed on the opposite side. Contrast was calculated from the ratio of luminance (transmitted light intensity) between when the polarization axis was parallel and when it was vertical.

  The color filters (Examples) prepared using the pigment composition of the present invention are different from those used in Comparative Examples 1 and 2 and the present invention using the composition without the addition of the triazine compound (β). Compared with Comparative Example 3 using a composition to which a triazine structure was added, the contrast after post-baking was excellent.

Claims (4)

Diketopyrrolopyrrole pigment (α) and the following formula (I)

(Wherein, X each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, a cyano group, a trifluoromethyl group, a nitro _group, C 1 -C ₈ alkyl _group, C 3 -C ₈ cycloalkyl A triazine compound (β) represented by a group, a C ₂ -C ₈ alkenyl group, a C ₁ -C ₈ alkoxy group, a phenyl group or a benzyl group). The diketopyrrolopyrrole pigment (α) is represented by the following formula (II)

The pigment composition for a color filter according to claim 1, wherein R is a chlorine atom, a bromine atom or a phenyl group. The color filter pigment according to claim 1, wherein the triazine compound (β) is contained in an amount of 0.1 to 10 parts per 100 parts of the diketopyrrolopyrrole pigment (α) in terms of mass. Composition. A color filter comprising the pigment composition according to any one of claims 1 to 3 in a red pixel portion.