JP2017097272A - Red pigment composition for color filter, method for producing the same, and color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a red pigment composition which has high contrast and high luminance even through a firing treatment when used in manufacture of a color filter, and achieves enhancement of handleability such as low viscosity and high fluidity when formed into a pigment dispersion body, and to provide a method for producing the composition and a color filter using the composition.SOLUTION: A red pigment composition contains a red organic pigment (A) and an acrylic resin skeleton-containing coloring material (B). The red pigment composition is used in manufacture of a color filter and thereby exhibits high contrast and high luminance, and the composition can achieve enhancement of handleability such as low viscosity and high fluidity when formed into a pigment dispersion body.SELECTED DRAWING: None

Description

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

  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.

  In general, the viscosity of the dispersion tends to increase as the primary particle size of the pigment decreases. In recent years, there has been an increasing demand for organic pigments for color filters that can improve the handling quality such as low viscosity and high fluidity when used as a pigment dispersion in addition to improving the quality such as high contrast and high brightness.

In order to meet such demands, as a method for producing an organic pigment for a color filter, for example, a mixture containing an organic pigment, a synthetic resin that is solid and water-insoluble at room temperature, and a water-soluble organic solvent is used. A method for producing a color filter pigment composition kneaded in the presence is known (Patent Document 1). Patent Document 1 suggests that an epoxy resin or a (meth) acrylic resin is used as a synthetic resin that is solid and water-insoluble at room temperature and used at the time of the kneading (solvent salt milling). And as this epoxy resin, bisphenol type, novolak type, alkylphenol type, resorcin type, polyglycol type, ester type, glycidyl type such as N-glycidylamine, cyclic aliphatic epoxide, etc. are described, and (meth) acrylic resin Describes copolymers of monomers or mixtures of acrylic acid and methacrylic acid monomers and their monomers, and copolymers with 60 mol% or less of radically polymerizable monomers such as styrene, vinyl acetate, maleic anhydride, etc. Etc. are described.
On the other hand, as a method for producing an organic pigment for a color filter, for example, a pigment composition for a color filter in which a mixture containing an organic pigment, an organic pigment derivative and a water-soluble organic solvent is kneaded in the presence of a water-soluble inorganic salt. A manufacturing method is known (Patent Document 2). Patent Document 2 describes diketopyrrolopyrrole derivatives, quinacridone derivatives, and the like as organic pigment derivatives used in the kneading (solvent salt milling).

Here, since the color filter is generally baked at a high temperature of 230 ° C. or higher, the organic pigment to be used is required to have a heat resistance of 230 ° C. or higher. High pigment compositions are required.
However, using only a synthetic resin that is solid and water-insoluble at room temperature as in Patent Documents 1 and 2 or kneading using only an organic pigment derivative, from the viewpoint of low contrast and brightness after firing. Not enough. Furthermore, the improvement of the handleability at the time of setting it as a pigment dispersion is also calculated | required. The actual situation is that pigments for color filters that satisfy these performance requirements that have been increasing in recent years have not been obtained.
Under such circumstances, there is a demand for creation of a pigment composition that has both high contrast and brightness even after firing, and further improved handling properties such as low viscosity and high fluidity when used as a pigment dispersion. Yes.

Japanese Patent Laid-Open No. 7-13015 JP 2001-220520 A

  The problem to be solved by the present invention is that when used for producing a color filter, a color filter with high contrast and brightness can be obtained even after baking treatment, and low viscosity and high fluidity when used as a pigment dispersion. An object of the present invention is to provide a red pigment composition that achieves both improved handling properties. Another object of the present invention is to provide a method for producing the composition and a color filter using the composition.

  The inventors of the present invention made extensive studies in order to solve the above-mentioned problems. As a result, the red pigment composition containing the red organic pigment (A) and the acrylic resin skeleton-containing color material (B) was used for color filter production. As a result, it was found that high contrast and high brightness were exhibited, and when the pigment dispersion was made, it was possible to achieve both improved handling properties such as low viscosity and high fluidity, and the present invention was completed.

That is, the present invention relates to the following.
Item 1. A red pigment composition for a color filter, comprising a red organic pigment (A) and an acrylic resin skeleton-containing color material (B).

Item 2. Item 2. The red pigment composition for a color filter according to Item 1, wherein the acrylic resin skeleton-containing color material (B) is a combination of an acrylic resin and a pigment or pigment derivative.

Item 3. Item 3. The red pigment composition for color filters according to Item 2, wherein the pigment or pigment derivative constituting the acrylic resin skeleton-containing color material (B) is a quinacridone pigment derivative or a diketopyrrolopyrrole organic pigment. object.

Item 4. 2. The color filter according to item 1, wherein the acrylic resin skeleton-containing color material (B) is a reaction product of a quinacridone pigment derivative or a diketopyrrolopyrrole organic pigment and an epoxy group-containing acrylic resin. Red pigment composition.

Item 5. Item 2. The red pigment composition for color filters according to Item 1, further comprising phthalimidoalkylated quinacridone as a pigment derivative.

Item 6. A first step of dissolving the red organic pigment (A) in a good solvent to obtain a pigment solution, a second step of taking out the pigment solution in a poor solvent to obtain particles, and the particles and acrylic resin skeleton obtained in the second step A color comprising the third step of mechanically grinding together with the contained colorant (B) or together with the particles obtained in the second step, the acrylic resin skeleton-containing colorant (B), and the phthalimidoalkylated quinacridone. A method for producing a red pigment composition for a filter.
Item 7. Item 7. The color according to Item 6, wherein the acrylic resin skeleton-containing color material (B) is obtained by reacting a quinacridone pigment derivative or a diketopyrrolopyrrole organic pigment with an epoxy group-containing acrylic resin. A method for producing a pigment composition for a filter.

Item 8. The color filter which uses the red pigment composition for color filters as described in any one of Claims 1-5 for a red pixel part.
Item 9. A color filter using the red pigment composition for a color filter obtained by the method according to claim 6 for a red pixel portion.

  When the pigment composition for a color filter of the present invention is used for a color filter, a color filter having high contrast and brightness can be produced even after firing in the color filter production process. Furthermore, the viscosity can be reduced when the pigment dispersion is formed. As described above, the present invention has an excellent effect of making it possible to achieve both high contrast and high brightness, and handleability when a pigment dispersion is used.

It is a GPC measurement result by UV absorption detector of the solid acrylic resin obtained by the reference example. It is a GPC measurement result with the UV absorption detector of the acrylic resin frame | skeleton containing color material obtained in Example 1. FIG. It is a GPC measurement result by the UV absorption detector of the acrylic resin skeleton containing color material obtained in Example 2.

  The pigment composition of the present invention is a red pigment composition for a color filter containing a red organic pigment (A) and an acrylic resin skeleton-containing color material (B).

<Red organic pigment (A)>
Examples of the red organic pigment (A) of the present invention include quinacridone, quinacridonequinone, perylene, perinone, diketopyrrolopyrrole, thioindigo, benzimidazolone, azo, and anthraquinone. be able to. Of these, diketopyrrolopyrrole and anthraquinone are preferable, and diketopyrrolopyrrole are more preferable. The red organic pigment (A) may be the same as or different from the organic pigment constituting the acrylic resin skeleton-containing color material (B) described later.

<Acrylic resin skeleton-containing color material (B)>
The acrylic resin skeleton-containing color material (B) of the present invention has a structure in which an acrylic resin skeleton and a pigment or pigment derivative are bonded, and can be obtained by the method described in JP-A-9-12916. More preferably, a resin skeleton having an epoxy group and a pigment or pigment derivative having an amino group are bonded. Specifically, an epoxy group having a resin skeleton and an amino group having a pigment or pigment derivative are included. It is in the form of being bound by an addition reaction.

  The pigment or pigment derivative constituting the acrylic resin skeleton-containing color material (B) may be any one as long as a structure combined with the resin skeleton is obtained as described in JP-A-9-12916. Quinacridone, quinacridone quinone, flavanthrone, perylene, perinone, diketopyrrolopyrrole, thioindigo, benzimidazolone, azo, anthraquinone, or derivatives of these pigments. . Among them, it is preferable to use a derivative of a quinacridone pigment such as a phthalimidoalkylated quinacridone, a diketopyrrolopyrrole organic pigment, or an anthraquinone organic pigment.

  The diketopyrrolopyrrole pigment is a red-orange pigment and has excellent light resistance and heat resistance. Examples of the diketopyrrolopyrrole pigment include C.I. I. Pigment red 254, C.I. I. Pigment red 255, C.I. I. Pigment red 264, C.I. I. And red pigments such as CI Pigment Red 272. In addition, C.I. I. Pigment orange 71, C.I. I. And orange pigments such as CI Pigment Orange 73. The diketopyrrolopyrrole pigment of the present invention is more preferably the following formula (II)

(Wherein, R represents a chlorine atom, a bromine atom or a phenyl group).

  As the resin skeleton constituting the acrylic resin skeleton-containing color material (B), various skeletons described in JP-A-9-12916 are used. In the present invention, it is general purpose to employ the acrylic resin skeleton. It is preferable in that the property is high and the effect of salt milling is remarkable.

  The number average molecular weight of the acrylic resin skeleton-containing color material (B) is preferably 500 to 30,000, more preferably 1,000 to 20,000. When the number average molecular weight of the acrylic resin skeleton-containing color material (B) is less than 500, the molecular weight is too low to improve the dispersion stability, and when it exceeds 30000, the viscosity is increased or the binder resin is used. It may cause aggregation due to a decrease in compatibility.

  The method for producing the acrylic resin skeleton-containing color material (B) used in the present invention is not particularly limited as long as it has a structure in which an acrylic resin skeleton and a pigment or pigment derivative are bonded, but from the viewpoint of cost and the like, The method described in JP-A-9-12916 is preferably used. This method is also adopted in the embodiments described later. Specifically, a pigment or a pigment derivative (specific examples are as described above) to be used for constituting the acrylic resin skeleton-containing color material (B) is dissolved in an aprotic polar solvent in the presence of a base, and then an epoxy group-containing acrylic. It can be produced by reacting with a resin. The equivalent ratio of the active hydrogen of the amino group in the pigment or pigment derivative to the epoxy group in the epoxy group-containing acrylic resin is preferably from 0.01 to 2.0, and more preferably from 0.2 to 1.0.

<Base>
Examples of the base include strongly basic inorganic compounds such as alkali metal hydroxides, alkali metal alkoxides, alkaline earth metal hydroxides, alkaline earth metal alkoxides; and strong organic bases. it can. Specific examples of the strongly basic inorganic compound include potassium hydroxide, sodium hydroxide, lithium hydroxide, potassium t-butoxide, potassium methoxide, potassium ethoxide, sodium methoxide, sodium ethoxide and the like. be able to. Examples of the strong organic base include hydroxides of quaternary ammonium compounds such as tetrabutylammonium hydroxide, 1,8-diazabicyclo [5,4,0] -7-undecene, 1,8-diazabicyclo [4]. , 3, 0] -5-nonene, guanidine, and the like. Two or more of these can be used in combination.

  The addition amount of the base is preferably 0.1 to 10 equivalents with respect to 1 equivalent of the organic pigment. If the addition amount is less than 0.1 equivalent, the solubility of the organic pigment is insufficient, and the reaction with the epoxy group-containing acrylic resin does not proceed sufficiently, and if it exceeds 10 equivalents, the base is difficult to dissolve in the solvent. Moreover, the increase of the effect by base addition cannot be expected. More preferably, it is 1-4 equivalent.

<Aprotic polar solvent>
The aprotic polar solvent is not particularly limited, and examples thereof include dimethyl sulfoxide, sulfolane, tetramethyl urea, hexamethyl phosphoramide, N-methyl-2-pyrrolidone, dimethylformamide, pyridine, quinoline, methyl benzoate, and the like. Can be mentioned. Of these, dimethyl sulfoxide, tetramethylurea, dimethylformamide, and sulfolane are preferable, and dimethyl sulfoxide is more preferable. Two or more of these can be used in combination.

  In order to improve the solubility of the base and epoxy group-containing acrylic resin in place of a part of the aprotic polar solvent, as other solvents, protic polar solvents such as water, methanol, ethanol, isopropanol; toluene, xylene Nonpolar solvents such as acetone; acetone; butyl acetate and the like can be used in combination. The blending amount of the other solvent is preferably such that the amount of the aprotic polar solvent is 50% by weight or more based on the total solvent.

  The amount of the aprotic polar solvent or the mixed solvent with the aprotic polar solvent and the other solvent used in combination instead of a part of the aprotic polar solvent is 1 part by weight of the organic pigment. The amount is preferably 5 to 200 parts by weight, more preferably 10 to 50 parts by weight.

<Epoxy group-containing acrylic resin>
Examples of the epoxy group-containing acrylic resin include a copolymer of glycidyl methacrylate and an alkyl (meth) acrylate, which has a number average molecular weight of 500 to 30,000 and an epoxy equivalent of 100 to 1,000, A number average molecular weight of 1000 to 20000 and an epoxy equivalent of 200 to 800 are more preferred.

  The addition amount of the epoxy group-containing acrylic resin is preferably 1 to 30 equivalents relative to 1 equivalent of the base. When the addition amount is less than 1 equivalent, the amount of the epoxy group-containing acrylic resin is too small, and when it exceeds 30 equivalents, the amount of the epoxy group-containing acrylic resin is too large to leave an unreacted epoxy group-containing acrylic resin, Moreover, it becomes difficult to dissolve in the solvent. More preferably, it is 1-10 equivalent. In preparing the epoxy group-containing acrylic resin used in the examples described later, various known and conventional methods such as a bulk polymerization method, a suspension polymerization method or a solution polymerization method can be employed. Thus, after the polymerization, the target epoxy group-containing acrylic resin can be produced by a conventional method.

<Temperature>
In the above reaction, the reaction temperature is preferably -30 to 120 ° C, more preferably 15 to 80 ° C.

  The progress of the reaction can be determined by sampling a part of the reaction solution and confirming the product by means such as titration, IR measurement, GPC measurement or the like.

<Recovery>
In the recovery, an acid aqueous solution or an alcoholic acid solution in an amount capable of neutralizing the base is added, and the neutralized reaction solution is added in an amount of 50 to 300 parts by weight, preferably 1 part by weight of the modified organic pigment. Can be carried out by putting it in 100 to 200 parts by weight of water to precipitate the reaction product, followed by filtration, washing with an organic solvent such as methanol and acetone, water, and drying.

  The pigment composition of the present invention comprises a red organic pigment (A) and an acrylic resin skeleton-containing color material (B), the latter being 0.1 to 30 parts, preferably 10 to 20 parts per 100 parts in terms of mass. It can prepare by making it contain.

  Color filter pigment compositions are often polymer coated for the purpose of ensuring better dispersibility in pigment dispersions such as color filter pastes described below and photocurable compositions such as resists. Although pigment particles are used, the pigment composition of the present invention can obtain sufficient dispersibility even if the organic pigment (A) is particles that are not coated with a polymer. However, the use of organic pigments coated with a polymer is not limited.

  In the pigment composition for a color filter of the present invention, other organic pigments or organic pigment derivatives may be used in combination for the purpose of toning and the like. 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. Further, sulfonic acid derivatives of diketopyrrolopyrrole pigments, sulfonic acid derivatives of quinacridone red pigments, and the like can be given. Among organic pigment derivatives, phthalimidoalkylated quinacridone such as phthalimidomethylated dichloroquinacridone is preferred.

  In the pigment composition of the present invention, the red organic pigment (A) occupies a mixture of the red organic pigment (A), the acrylic resin skeleton-containing color material (B), and other organic pigments or organic pigment derivatives added as necessary. And the acrylic resin skeleton-containing color material (B), the greater the ratio, the higher the effect of the present invention. Among other organic pigments and organic pigment derivatives, in the case of phthalimidoalkylated quinacridone, 1 to 100 parts can be contained per 100 parts in total of the organic pigment (A) and the resin skeleton-containing color material (B). , Preferably 1-30 parts, More preferably, 1-20 parts can be contained.

  These other organic pigments and organic pigment derivatives may also be those coated with a polymer as described above.

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

  The red organic pigment composition of the present invention comprises a step of obtaining a pigment solution by dissolving the organic pigment (A) in a basic solvent (first step), and taking out the pigment solution into an acidic to neutral solution. The step of obtaining fine and uniform pigment particles (referred to as the second step), the pigment particles obtained in the second step, and the acrylic resin skeleton-containing color material (B), or obtained in the second step Together with the pigment particles, the acrylic resin skeleton-containing color material (B) and the pigment derivative, it can be produced by three steps of a particle control step (referred to as a third step) by mechanical grinding. 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 pigment solution in which the pigment prepared in the first step is dissolved into an acidic to neutral solution. In the third step, together with the pigment particles obtained in the second step and the acrylic resin skeleton-containing color material (B) or the pigment particles obtained in the second step, the acrylic resin skeleton-containing color material (B) and the pigment derivative, This is a step of obtaining a fine secondary particle organic pigment composition by mechanically grinding a mixture of an inorganic salt and an organic solvent. 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 red organic pigment (A) uniformly in the 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. When a condensed polycyclic pigment such as a diketopyrrolopyrrole pigment is used as in the examples described later, dimethyl sulfoxide is preferred because the condensed polycyclic pigment has high solubility.

  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 in any proportion as long as the organic pigment (A) is dissolved. However, in consideration of productivity, it is preferably 0.2 to 10 parts with respect to 100 parts of the mixed solution. 0.5 to 5 parts is preferred.

  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 pigment 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 for taking out the pigment 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]
The pigment particles obtained in the second step together with the acrylic resin skeleton-containing color material (B) or the pigment particles obtained in the second step together with the acrylic resin skeleton-containing color material (B) and the pigment derivative are mechanically ground. This is a process for producing a pigment composition for a color filter which is a fine primary particle which is the final purpose. In this step, it is more preferable to mechanically grind the pigment particles obtained in the second step together with the acrylic resin skeleton-containing color material (B) and the pigment derivative.

  One suitable method of mechanical attrition includes solvent salt milling. Solvent salt milling means kneading an organic pigment, other raw materials, an inorganic salt, and a hydrophilic organic solvent. Specifically, an organic pigment, other raw materials, an inorganic salt, and a hydrophilic organic solvent that does not dissolve the organic pigment are charged into a kneader, and kneading and grinding are performed therein. Examples of the kneading means at this time include kneaders such as a kneader and a mix muller.

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

  In obtaining the preferred organic 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. However, it is preferably 7 to 30 parts, particularly 10 to 30 parts.

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

  Although the usage-amount of an organic solvent is not specifically limited, 0.01 mass per 1 part of the total of the mixture containing an organic pigment (A) and an acrylic resin frame | skeleton containing color material (B) as an essential component in conversion of mass. ~ 5 parts are preferred.

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

  In the solvent salt milling process, the inorganic salt and the organic solvent as described above are charged with the necessary amount in the initial charging stage and then the organic pigment (A) and the acrylic resin skeleton-containing colorant (B) as essential components. Grinding may be performed until the mixture containing the above-mentioned required primary particles has an average particle diameter, or only a part of the necessary amount is charged and milling is started. Grinding may be performed so that the remaining amount is charged all at once or divided.

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

  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 organic pigment composition of this invention can be obtained by performing.

As this cleaning method, either water washing or hot water washing can be employed. In the case of the mixture using a water-soluble inorganic salt and an organic solvent, the organic solvent and the inorganic salt can be easily removed by washing with water. It is preferable that the material having the specific conductivity is removed as much as possible. In particular, it is preferable to perform washing until the specific conductivity of the pigment composition of the present invention for preparing the color filter pixel portion is 50 μS / cm or less, preferably 20 μS / cm or less. Here, the method for measuring the specific conductivity of the pigment composition is 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 the remaining 100 mL with a graduated cylinder.
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 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 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. I can do it. As described above, a red pixel portion and a pigment for forming a 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 for forming a pixel portion of a color filter (also referred to as a pigment-dispersed photoresist) includes the pigment composition of the present invention, a dispersant, a photocurable compound, and an organic solvent as essential components. It can be prepared by mixing these using a thermoplastic resin if necessary. When the colored resin film that forms the pixel portion requires toughness that can withstand baking performed in the actual production of a color filter, only the photocurable compound is prepared 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 pixel part of the filter, add a photocurable compound and, if necessary, a thermoplastic resin or a photopolymerization initiator. The method of making the said photocurable composition is common.

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

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

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

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

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

  Using each of the materials as described above, the pigment composition of the present invention is, in terms of mass, uniformly 300 to 1,000 parts of an organic solvent and 0 to 100 parts of a dispersant per 100 parts. The pigment dispersion can be obtained by stirring and dispersing so that Next, the pigment dispersion is subjected to photopolymerization of 3 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 organic pigment composition of the present invention. A photocurable composition for forming a color filter 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. Such a photocurable composition is usually prepared such that the average particle size of the dispersed particles is 100 nm or less.

  The pigment dispersion and the 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 centrifugal separation, sintered filter, membrane filter or the like. Preferably, it is preferable to remove coarse particles of 0.5 μm or more and mixed dust.

  As the developer, a publicly known and commonly used organic solvent or alkaline aqueous solution can be used. In particular, when the photocurable composition contains a thermoplastic resin or a photocurable compound, and at least one of them has an acid value and exhibits alkali solubility, the color filter can be washed with an alkaline aqueous solution. 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 organic pigment composition of the present invention is a different electrodeposition method. The color filter may be manufactured by forming the 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 photocurable composition of each color obtained by using a blue organic pigment composition, a green organic pigment composition, and a red organic pigment composition, and encapsulates a liquid crystal material between a pair of parallel transparent electrodes. The transparent electrode is divided into discontinuous fine sections, and red (R), green (G), and blue (B) are divided into fine sections divided in a lattice pattern by the black matrix on the transparent electrode. It can be obtained by providing a color filter coloring pixel portion selected from any one color alternately in a pattern, or by forming a color filter coloring pixel portion on a substrate and then providing a transparent electrode.

  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 can also be used.

  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. In the examples, the epoxy equivalent and the GPC measurement method are as follows.
[Measurement method of epoxy equivalent]
It measured by the hydrochloric acid-pyridine method. To the resin, 25 ml of a hydrochloric acid-pyridine solution was added and dissolved by heating at 130 ° C. for 1 hour, and then titrated with a 0.1 N potassium hydroxide alcohol solution using phenolphthalein as an indicator. The epoxy equivalent was calculated by the amount of 0.1N potassium hydroxide alcohol solution consumed.
[GPC measurement conditions]
Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.
“TSKgel G5000HxL” (7.8 mm ID × 30 cm) × 1 “TSKgel G4000HxL” (7.8 mmID × 30 cm) × 1 “TSKgel G3000H × L” (7.8 mm ID × 30 cm) × 1 “TSKgel G2000HxL” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer; 40 ° C.), UV absorption detector (measurement wavelength: 254 nm)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 4 mg / mL (standard PSt concentration of 0.1 mg / mL))
Standard sample: A calibration curve was prepared using the following monodisperse polystyrene (standard PSt concentration 0.1 mg / mL).
(Monodispersed polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-380" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-450" manufactured by Tosoh Corporation
In addition, about the resin frame | skeleton containing coloring material, after preparing the tetrahydrofuran solution with a sample density | concentration of 4 mg / mL, it left still overnight, after centrifugation, extract | collected the supernatant liquid, filtered, and measured on the said conditions.

Preparation of epoxy group-containing acrylic resin <Reference Example 1>
A reaction vessel equipped with a stirrer, a thermometer, a cooling pipe and a nitrogen introduction pipe was charged with 470 parts by mass of xylene and heated to 135 ° C. in a nitrogen atmosphere. There, a mixture consisting of 61 parts by weight of methyl methacrylate, 10 parts by weight of n-butyl methacrylate, 29 parts by weight of glycidyl methacrylate and 5 parts by weight of tert-butylperoxy-2-ethylhexanoate was taken over 6 hours. It was dripped. After completion of the dropwise addition, the mixture was kept at the same temperature for 10 hours to conduct the polymerization reaction, and then the solvent was distilled off under reduced pressure of 20 mmHg at 170 ° C. A containing acrylic resin was obtained. The GPC measurement results are shown in FIG.

<Example 1>
Preparation of acrylic resin skeleton-containing color material In a reaction vessel equipped with a thermometer and a stirrer, dichlorodiketopyrrolopyrrole ("Irgazin RED L3837HD", CI Pigment Red 254) manufactured by BASF) 3.57 parts by weight, potassium -1.12 weight part of t-butoxide, 15.0 weight part of isopropanol, and 35.0 weight part of dimethyl sulfoxide were added, and it stirred at 25 degreeC until solid content melt | dissolved, and dissolved solid content. Subsequently, 20.0 parts by weight of the solid epoxy group-containing acrylic resin obtained in Reference Example 1 was previously dissolved in 12.5 parts by weight of xylene and 12.5 parts by weight of n-butyl acetate. The mixture was further stirred at 60 ° C. for 6 hours. After stirring, 10.0 parts by weight of a 1N hydrochloric acid aqueous solution is added to neutralize to precipitate a red product, 50.0 parts by weight of n-butyl acetate is added, washed with water and methanol, and then dried under reduced pressure. A solid color material containing a resin skeleton was obtained. From the GPC measurement result of the reaction product with a UV absorption detector, an increase in the height of the GPC curve was recognized compared with the epoxy group-containing acrylic resin obtained in Reference Example 1. Therefore, dichlorodiketopyrrolo having a high UV absorbance. It was confirmed that pyrrole was added with acrylic resin. The weight average molecular weight was 9,600. The GPC measurement results are shown in FIG.

Production of salt milled pigment (first step)
C. I. It was dissolved in a mixed solvent of 50 parts of Pigment Red 254, 1500 parts of dimethyl sulfoxide and 55 parts of a 28 wt% methanol solution of sodium methoxide, and stirred at 110 ° C. for 1 hour.
(Second step)
On the other hand, the pigment solution was dropped into a container in which 2300 parts of water and 2700 parts of ice were mixed with vigorous stirring, and stirred for 1 hour after the completion of dropping. The obtained pigment suspension was filtered with Nutsche, and washing with water was repeated until the pH of the filtrate was 8 or less. Thereafter, the mixture was dried and pulverized at 90 ° C. for 20 hours to obtain 42 parts of a red pigment composition.
(Third step)
30 parts of the red pigment composition prepared in the second step, 6 parts of phthalimidomethylated dichloroquinacridone, 4 parts of an acrylic resin skeleton-containing coloring material, 400 parts of sodium chloride, and 70 parts of diethylene glycol are made of a stainless steel 1 L kneader (Yoshida Manufacturing Co., Ltd.) 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 washed repeatedly with water until the specific conductivity was 150 μS / cm or less to remove sodium chloride and the solvent. Thereafter, the mixture was dried and pulverized at 90 ° C. for 20 hours to obtain 35 parts of a red pigment composition for a color filter.
(Evaluation process)
2 parts of the red pigment composition obtained in the third step is put into a plastic bottle, 11 parts of propylene glycol monomethyl ether acetate, 2.3 parts of DISPERBYK (trade name) LP N 21116 (manufactured by Big Chemie Co., Ltd.), 0.3 part −0.4 mmφ Sepul beads were added and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.) to obtain a pigment dispersion. The viscosity immediately after dispersion of the obtained pigment dispersion was measured.
1.3 parts of the obtained pigment dispersion and 3.7 parts of acrylic resin solution Unidic (registered trademark) ZL-295 (manufactured by DIC Corporation) were stirred with a dispersion stirrer (MAZERUSTAR, Kurashiki Boseki Co., Ltd.), and a color filter. A composition for forming a red pixel portion was obtained. The composition was applied onto a glass substrate by a spin coater. The spin coater was rotated at 900, 1000, 1100, and 1200 rpm, and four types of glass plates having different coating film thicknesses were prepared. Each glass plate coated with the composition thus obtained was heated at 90 ° C. for 3 minutes to obtain a red pixel portion for a color filter, and the luminance, chromaticity and contrast were measured. Thereafter, the red pixel portion for the color filter was further baked at 230 ° C. for 1 hour, and the luminance, chromaticity, and contrast were measured.

<Example 2>
In the adjustment of the color material containing the resin skeleton of Example 1, 3.57 parts by weight of dichlorodiketopyrrolopyrrole (“Irgazin RED L3837HD”, CI Pigment Red 254) manufactured by BASF) 6.52 parts by weight of phthalimidomethylated dichloroquinacridone 6.52. The operation was performed in the same manner as in Example 1 except that the parts were changed to parts by weight. From the GPC measurement result of the obtained reaction product using a UV absorption detector, it was confirmed that phthalimidomethylated dichloroquinacridone was added to the acrylic resin. The weight average molecular weight was 8,000. The GPC measurement result of the reaction product with a UV absorption detector is shown in FIG.

<Comparative example>
In the salt milling process of Example 1, the salt milling process was performed in the same manner as in Example 1 except that the resin skeleton-containing color material used in Example 1 was changed to the epoxy group-containing acrylic resin prepared in Reference Example 1. A color filter was created.

The contrast, chromaticity, and luminance values after baking at 230 ° C. of the color filters prepared in the above-described Examples and Comparative Examples were measured and calculated according to the following measurement methods. The results are shown in Table 1. Table 1 also shows the viscosity of the pigment dispersions used in Examples and Comparative Examples.
[Contrast measurement method]
The obtained color filter red pixel portion was measured using a contrast tester CT-1 (manufactured by Aisaka Electric Co., Ltd.). 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.
[Measurement method of luminance and chromaticity x, y]
Using a spectrophotometer U3900 (manufactured by Hitachi High-Tech Science Co., Ltd.), luminance and chromaticity x, y in a C light source were measured.
[Measurement method of viscosity]
It measured with viscometer TVE-25L (made by Toki Sangyo Co., Ltd.).

  It can be seen that the color filters (Examples) prepared using the pigment composition of the present invention have higher contrast and brightness after firing than the comparative examples, and have achieved low viscosity as a pigment dispersion.

  The coexistence of the acrylic resin skeleton-containing color material (B) of the present invention at the time of solvent salt milling in the color filter production process produces an effect of adsorbing and protecting the organic pigment (A) due to the action of the color material site. Particle growth at the crystal type transition of the pigment (A), particle growth due to solvent contact, and drying aggregation at the time of coating film production are produced, resulting in low viscosity, high contrast and high brightness when used as a pigment dispersion. Is estimated to be possible. On the other hand, it is presumed that the heat resistance is improved by the action of the resin portion of the resin skeleton-containing color material (B), leading to higher contrast and higher brightness after firing.

Claims (7)

A red pigment composition for a color filter, comprising a red organic pigment (A) and an acrylic resin skeleton-containing color material (B). The red pigment composition for a color filter according to claim 1, wherein the acrylic resin skeleton-containing color material (B) is a color material in which an acrylic resin and a pigment or a pigment derivative are bonded. The red pigment composition for a color filter according to claim 2, wherein the pigment or pigment derivative constituting the acrylic resin skeleton-containing color material (B) is a quinacridone pigment derivative or a diketopyrrolopyrrole organic pigment. object. The red pigment composition for a color filter according to claim 1, further comprising phthalimidoalkylated quinacridone as a pigment derivative. A first step of dissolving the red organic pigment (A) in a good solvent to obtain a pigment solution, a second step of taking out the pigment solution in a poor solvent to obtain particles, and the particles and acrylic resin skeleton obtained in the second step A color comprising the third step of mechanically grinding together with the contained colorant (B) or together with the particles obtained in the second step, the acrylic resin skeleton-containing colorant (B), and the phthalimidoalkylated quinacridone. A method for producing a red pigment composition for a filter. The color according to claim 5, wherein the acrylic resin skeleton-containing color material (B) is obtained by reacting a quinacridone pigment derivative or a diketopyrrolopyrrole organic pigment with an epoxy group-containing acrylic resin. A method for producing a pigment composition for a filter. The color filter which uses the red pigment composition for color filters as described in any one of Claims 1-4 for a red pixel part.

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