JP5703550B2 - Refined pigment composition and method for producing pigment dispersion using the refined pigment composition - Google Patents

Description

  The present invention relates to a refined pigment composition and a method for producing a pigment dispersion using the refined pigment composition, and various inks for ink jet printers and color filters (including photolithography and ink jet color filters). The present invention relates to a finely divided pigment composition used for dispersions for color, color toners, and the like, and a method for producing a pigment dispersion using the finely divided pigment composition.

  Conventionally, organic pigments (hereinafter sometimes simply referred to as “pigments”) have been used as coloring materials for paints, printing inks, and resins. The particle size of pigments used in such applications is about 0.1 μm. It was a thing. In recent years, attention has been paid to excellent properties such as heat resistance, light resistance, and water resistance of pigments, and they have been used for various applications. For example, coloring materials for resin products that require transparency, liquid crystal displays, etc. It is also widely used in applications such as coloring materials for apparatus color filters, inkjet inks, and electrophotographic developers. Among these applications, pigments used in color filters, inkjet inks, etc. have strong improvements in handling properties such as low viscosity and high fluidity, in addition to improvements in coloring effects such as coloring power, hue, and transparency. There is a demand, and it is difficult to cope with conventional pigments.

  As a method for coping with such an improvement in the coloring effect, a method for obtaining a finer pigment in a uniformly dispersed state has been studied. It is considered necessary to make the particle diameter as small as possible. There are various known techniques for refining pigments. A salt milling method in which a composition containing a crude pigment, a water-soluble inorganic salt, a water-soluble solvent and the like is kneaded with a kneader or the like is used for refining and adjusting. Widely adopted because it is effective in terms of grains.

  However, when the pigment is refined by a salt milling method, generally, the composition is kneaded with a kneader, washed with water, dehydrated, dried with a box dryer or a band dryer, and further with a hammer mill or the like. Since the powder is pulverized and used as a pigment for various applications, even if a certain fine pigment is obtained by salt milling, a desired pigment dispersion is obtained through a subsequent drying and pulverization step. At this stage, strong agglomeration occurs or reagglomeration easily occurs, so that a sufficient coloring effect cannot be obtained and the viscosity increases with time.

  For such problems, attempts have been made to add a pigment derivative during milling, adjust the temperature during milling, or atomize a water-soluble inorganic salt such as salt (Patent Documents 1 to 3). ). Further, without passing through the drying step as described above, the water paste of the pigment after dehydration and a predetermined solvent are mixed, and the pigment is dispersed by flushing (which means phase inversion and may be used synonymously hereinafter). A method for obtaining a body has also been attempted (Patent Document 4).

  However, even if these methods are used, in practice, when TEM (transmission electron microscope) observation is performed, the primary particle diameter of the pigment is larger than 10 nm, and the primary particle diameter should be 10 nm or less. Is almost impossible or extremely difficult. In general, as the primary particle size decreases, reaggregation easily occurs and the viscosity of the pigment dispersion is likely to increase. Therefore, it is extremely difficult to obtain a pigment dispersion in which the finely divided pigment is stably dispersed. It is. Therefore, there is a problem that appropriate power is required to redisperse the pigment.

JP 2003-57425 A JP 2006-335920 A JP 2008-50588 A JP 2007-191699 A

  The present invention has been made to solve the above-mentioned problems, and the purpose of the present invention is to provide a pigment finer than a conventional finer pigment, in particular, a primary particle diameter of 10 nm or less and a finer pigment. It is to provide a finely divided pigment composition that is stably dispersed, and a method for producing a pigment dispersion containing the finely divided pigment composition.

  As a result of intensive studies to solve the above-mentioned problems, the present invention uses an additive suitable for the water-soluble solvent used in conventional solvent salt milling, whereas the pigment dispersion has Focusing on the fact that a solvent different from that used during salt milling and a dispersant suitable for the solvent are used, the concept of consistent non-aggregation from the miniaturization of organic pigments to the production of pigment dispersions Incorporating and forming an equivalent dispersion stabilization system from start to finish, it is possible to easily refine the pigment by performing a series of operations in the dispersion stabilization system, from salt milling to the manufacture of pigment dispersions. The present inventors have found that it is possible to produce a dispersion dispersion-stabilized pigment dispersion. That is, the gist of the present invention is as follows.

(1) A dispersion-stabilized pigment composition comprising an organic pigment, a dispersion-stabilizing solvent and a dispersant, and a mixture containing a water-soluble inorganic salt are kneaded and ground, then washed and dehydrated to obtain a finer pigment composition. A dispersion phase stabilization process comprising: a micronization process to obtain, a solvent phase inversion process in which the micronized pigment composition and the solvent are charged into a flasher, the pigment is phase- inverted from an aqueous phase to an oil phase, and then decanted to remove water. The pigmented pigment composition satisfies the following conditions, and the dispersion stabilizing solvent and the dispersant contained in the mixture in the refinement step are the same as the solvent and the dispersant used in the solvent phase inversion step. A method for producing a pigment dispersion.
Dispersion-stabilized pigment composition: For a dispersion-stabilized pigment composition having a pigment concentration of about 5 to 20% by weight, the viscosity at a shear rate of 10 [1 / sec] and 100 [1 / sec] is measured with a rheometer. The viscosity when the shear rate is 10 [1 / sec] is 100 [mPa · s] or less, and the TI value = (viscosity when 10 [1 / sec]) / (100 [1 / sec]. ] Is 1.5 or less.

(2) The method for producing a pigment dispersion according to (1), wherein the dispersion stabilizing solvent is an alkylene glycol lower alkyl ether acetate .

(3) The method for producing a pigment dispersion according to (2 ), wherein the alkylene glycol lower alkyl ether acetate is at least one selected from propylene glycol monomethyl ether acetate (PMA) and ethyl diglycol acetate (EDGAC) .

( 4 ) The method for producing a pigment dispersion according to ( 1 ), wherein in the solvent phase inversion step, water is decanted and removed, and then distilled under reduced pressure.

( 5 ) The method for producing a pigment dispersion according to ( 1 ), wherein the residual moisture in the pigment dispersion is reduced to 1.0% by weight or less by distillation under reduced pressure.

( 6 ) The method for producing a pigment dispersion according to ( 1 ), wherein the organic pigment contains a derivative of an organic pigment.

  According to the present invention, by incorporating the concept of consistent non-aggregation from the refinement of organic pigments to pigment dispersions, and by salt milling with a composition that forms a dispersion stable system, the primary particle size is reduced to 10 nm or less. A fine pigment composition containing a pigment can be easily provided. Moreover, since it can be used for the preparation of a pigment dispersion in the form of a pigment water paste without passing through a drying step or the like, a fine and uniform pigment dispersion excellent in dispersion stability without reaggregation is obtained with a small power, that is, It can be provided at low cost.

  The significance of the present invention is that it incorporates the concept of consistent non-aggregation from the miniaturization of organic pigments to the production of pigment dispersions, forms an equivalent dispersion stabilization system from beginning to end, and produces pigment dispersions from salt milling. By carrying out the process, it is possible to finally obtain a pigment dispersion in which a very fine pigment is stably dispersed.

  From such a viewpoint, the fine pigment composition of the present invention is obtained by grinding and kneading a mixture containing an organic pigment, a water-soluble inorganic salt, a dispersion stabilizing solvent and a dispersant, washing with water, and dehydrating. A pigment dispersion obtained by removing the water-soluble inorganic salt, wherein the combination of the organic pigment, the dispersion stabilizing solvent and the dispersant is prepared using the micronized pigment composition A combination of organic pigment, solvent and dispersant (corresponding to “dispersion stable composition of pigment” required for the final product) or a function having the same function .

  That is, in the present invention, a combination of a solvent and a dispersant suitable for the pigment selected according to the intended use of the finally obtained pigment dispersion is adopted from the stage of salt milling to form a dispersion stable system. It is characterized by this. This makes it possible to obtain a finely divided pigment composition that maintains the state when the pigment is miniaturized, and by using the finely divided pigment composition, a pigment dispersion containing a finely divided pigment suitable for a desired application can be obtained. It can be easily obtained.

  Therefore, in the present invention, when the use of the pigment dispersion is first determined, a combination of an organic pigment, a solvent, and a dispersing agent suitable for forming a dispersion stability system is determined for the use, and the combination is determined as a salt of the organic pigment. In principle, it will be adopted from the time of milling. However, the combination at the time of salt milling does not necessarily match the combination of the pigment, solvent and dispersant used in the pigment dispersion, and the solvent and dispersant used in combination with the pigment in the pigment dispersion It is possible to use a solvent or a dispersant having an equivalent function. In the present invention, such a combination is referred to as “a combination having an equivalent function”. Therefore, by using such a combination, the obtained pigment dispersion can form a dispersion stabilization system as described later.

  For example, in the case of using toluene as a solvent in the pigment dispersion, among the solvents that are equivalent to toluene, that is, compatible with toluene and do not hinder the action of the dispersant used in combination with toluene, In salt milling, a solvent selected from the viewpoint of health and safety and cost can be used as the dispersion stabilizing solvent. For example, butyl alcohol, propylene glycol monomethyl ether acetate and the like. In this way, it is possible to carry out a finer treatment in a dispersion stable system in place of a solvent that is substantially difficult to use during salt milling.

In the present invention, “to form a dispersion stable system” means that in the salt milling composition or the pigment dispersion composition, the finely divided pigment does not form an aggregated state such as flocculation or agglomeration, This means that a state close to monodispersion is maintained, and re-aggregation is not performed or a state in which re-aggregation hardly occurs is formed.
In the present invention, focusing on the fact that the viscosity of the pigment dispersion increases when re-aggregating, the pigment dispersion forms a dispersion stable system using the thixotropic index (TI value), which is an index of Newtonian flow. It is evaluated whether it is in the state which was done. Specific evaluation criteria are as follows.
That is, for the pigment dispersion, the viscosity at a shear rate of 10 [1 / sec] and 100 [1 / sec] is measured using a rheometer, and the viscosity at a shear rate of 10 [1 / sec] is measured. 100 [mPa · s] or less, TI value = (viscosity at 10 [1 / sec]) / (viscosity at 100 [1 / sec]) is 1.5 or less, more preferably 1.2 or less In this case, the pigment dispersion is in a state of forming a dispersion stabilization system. Moreover, the pigment dispersion here means the pigment dispersion of the present invention finally obtained in principle. However, when the dispersion stabilization system of the dispersion in the production process or in the final state is confirmed in advance, the pigment concentration is generally 5 to 20% by weight (when a pigment derivative is used, the pigment derivative is included), and the dispersant. Means a pigment dispersion for confirmation prepared using a dispersion stabilizing solvent or the like.
Moreover, in this invention, it can consider as an auxiliary | assistant confirmation method about a dispersion stable system using the haze showing the transparency of the coating film which is one parameter | index of dispersibility confirmation. However, haze is not necessarily expressed as an absolute value because the measured value varies depending on the measurement conditions. For example, in the case of adopting the dispersion stability confirmation test method described later, the haze is 15 or less. Is one measure of dispersion stability.
And the pigment dispersion which forms the state which appears in such a numerical value is excellent in fluidity | liquidity, and becomes excellent in color characteristics, such as a saturation and a density | concentration.

  Among the fields that require that the above highly refined pigment is stably dispersed, here, the color filter is taken as an example, and the method for producing the refined pigment composition of the present invention is described below. explain.

<Refining process>
In the present invention, the organic pigment is refined using a salt milling method. In this method, an organic pigment, an inorganic milling agent, a dispersant, and a solvent (in the present invention, particularly referred to as a dispersion stabilizing solvent) are mixed, and a so-called pigment dispersion-stabilizing composition is mixed using a kneader or the like. This is a method of mechanically kneading and kneading (the mixture kneaded and kneaded in this way may be referred to as magma) to refine the organic pigment. In the present invention, a mixture comprising an organic pigment, a dispersion stabilizing solvent and a dispersing agent is also referred to as a dispersion stabilizing pigment composition.

  The dispersion stabilizing solvent needs to be set based on the use of the pigment dispersion as described above, but as a solvent for preparing the pigment dispersion, alcohol solvents, ketone solvents, ester solvents are generally used. A solvent, an ether solvent, an aliphatic hydrocarbon solvent, or an aromatic hydrocarbon solvent can be used. More specifically, it is as follows.

Examples of alcohol solvents include butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, cyclohexanol, benzyl alcohol, amyl alcohol, and the like.
Examples of ketone solvents include methyl ethyl ketone, methyl isobutyl kenton, cyclohexanone, ethyl amyl ketone, diisobutyl ketone, and methyl cyclohexanone.

  Examples of ester solvents include ethyl acetate, n-butyl acetate, ethyl lactate, methyl ethoxypropionate, ethyl ethoxypropionate, and the like.

  Examples of the ether solvent include ethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate and the like.

  Examples of the aliphatic hydrocarbon solvent include n-pentane, n-hexane, and n-heptane, and examples of the aromatic hydrocarbon solvent include toluene, o-xylene, m-xylene, and p-xylene. .

  Of the above solvents, particularly preferred is at least one selected from the group consisting of cyclohexanone, methyl ethoxypropionate, ethyl ethoxypropionate, propylene glycol monomethyl ether acetate and the like. Even in this case, it goes without saying that it is necessary to set based on the use of the pigment dispersion.

  Moreover, when preparing a pigment dispersion for color filters, an ether solvent can be used. In the salt milling, as described above, a solvent selected from the viewpoints of safety in terms of work safety and cost from the solvent species of the pigment dispersion for the color filter can be preferably used as the dispersion stabilizing solvent. More preferably, a solvent that is water-soluble or has some solubility in water is suitable from the viewpoint of ease of operation in the step of removing the water-soluble inorganic salt. Solvents belonging to the ether acetate group are preferably used.

  More specifically, ethyl cellosolve acetate, butyl cellosolve acetate, 1-methoxy-2-propyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol mono Examples include ethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol diacetate, propylene glycol diacetate, 3-methoxybutyl acetate, and 3-methoxy-3-methylbutyl acetate. Of these, propylene glycol monomethyl ether acetate is particularly preferably used. This is because the dispersion for a photolithographic system is the most easy-to-handle solvent in the color filter manufacturing process, such as compatibility with a resist resin, fluidity in the case of patterning such as a printing method and a transfer method, and a drying speed.

  The reason why these specific dispersion stabilizing solvents contribute to the dispersion stability of pigments in magma, particularly the dispersion stability of ultrafine pigments with a primary particle size of 10 nm or less, is the newly generated surface and dispersion caused by milling. This is thought to be because it facilitates the efficient bonding and adsorption of the agent and prevents the adverse effects of water in the subsequent washing and desalting step. In addition, it is presumed that the pigment dispersion has good compatibility with the film forming resin of the color filter and suppresses aggregation during mixing.

  The amount of the dispersion stabilizing solvent used in the refinement step is not particularly limited, and the viscosity and hardness of the magma that can obtain a shearing force by which the pigment is effectively ground by the water-soluble inorganic salt during salt milling. What is necessary is just to determine suitably so that it can hold | maintain.

  In the present invention, the organic pigment to be used is not particularly limited, but for example, at least one selected from azo pigments, phthalocyanine pigments, and condensed polycyclic pigments can be used. The condensed polycyclic pigments include anthraquinone pigments, quinacridone pigments, indigo pigments, dioxazine pigments, perylene pigments, perinone pigments, isoindolinone pigments, isoindoline pigments, metal complex pigments, and quinophthalone pigments. Examples thereof include pigments and diketopyrrolopyrrole pigments.

  In the present invention, in the combination of the organic pigment and the dispersion stabilizing solvent, a dispersant exhibiting the function of crystal stabilization, easy dispersion, and / or dispersion stabilization can be used. An activator type pigment dispersant can be used.

  Specific examples of resin-type pigment dispersants include polyurethanes, polyesters, unsaturated polyamides, phosphoric esters, polycarboxylic acids and their amine salts / ammonium salts / alkylamine salts, polycarboxylic acid esters, hydroxyl group-containing polycarboxylic acid esters, polysiloxanes , Oil-based dispersants such as modified polyacrylates, water-soluble resins such as (meth) acrylic acid- (meth) acrylic acid ester copolymers, (meth) acrylic acid-styrene copolymers, styrene-maleic acid copolymers, Water-soluble polymer compounds are used, and these can be used alone or in admixture of two or more. The resin type pigment dispersant preferably has a weight average molecular weight of about 1000 to 30000.

  Specifically, Solsperse 3000, 9000, 13240, 17000, 20000, 24000, 26000, 28000, 32000, 32500, 41000 (manufactured by Nippon Lubrizol Co., Ltd.), Disperbyk-108, 110, 112, 140, 142 145, 161, 162, 164, 166, 2000, 2001, 2050, 2070, 2150 (above, manufactured by Big Chemie Japan Co., Ltd.), EFKA-4401, 4403, 4406, 4010, 4015, 4046, 4047, 4050, 4055, 4060, 4080, 5064, 5207, 5244 (manufactured by EFKA Additive), Azisper PB821 (F), PB822, PB880 (manufactured by Ajinomoto Fine Techno Co., Ltd.), Hinoac T-8000 (manufactured by Kawaken Fine Chemicals Co., Ltd.), Disparlon PW-36, DA-325,375,7301 (Kusumoto Kasei Co., Ltd.), and the like.

  Surfactant type pigment dispersants include naphthalene sulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate, anion activator such as polyoxyethylene alkyl phosphate, nonionic activator such as polyoxyethylene alkyl ether, alkyl Examples include cation activators such as amine salts and quaternary ammonium salts.

  Specifically, Demol N, RN, MS, SN-B, Emulgen 120, 430, Acetamine 24, 86, Coatamine 24P (above, manufactured by Kao Corporation), Prisurf AL, A208F (above, Daiichi Kogyo Seiyaku) Manufactured by Co., Ltd.), ARCARD C-50, T-28, T-50 (and above, Lion Corporation), and the like.

  Examples of the water-soluble inorganic salt include sodium chloride (sodium chloride), mirabilite (including sodium sulfate and anhydride), potassium chloride and the like.

  In the present invention, derivatives of organic pigments used for crystal stabilization and dispersion stabilization may be added as appropriate. This derivative is a compound that uses the organic pigment as the basic skeleton and introduces a substituent that imparts acidity or a basicity that imparts basicity in the molecule, and adsorbs to the pigment to be dispersed to give polarity. Thus, it is considered that a dispersion effect is given from the interaction with the dispersant and the resin.

  Specifically, in addition to the synthetic product at Sanyo Dye Co., Ltd., as examples of commercially available products, EFKA-6745, 6750 (manufactured by EFKA Additive), BYK-Synergist 2100 (manufactured by Big Chemie Japan Co., Ltd.), Solsperse 5000, 12000, 22000 (Nippon Lubrizol Co., Ltd.) etc. are mentioned.

In the present invention, in order to impart an auxiliary effect to the dispersant, as a dispersion aid that does not adversely affect the performance as a color filter, it is soluble in the dispersion stabilizing solvent, but is insoluble in water and has a room temperature. Then, a synthetic resin that becomes a solid state can be added. In addition, a fiber derivative, a rubber derivative, or a protein derivative may be selected and used according to the synthetic resin.
Of these synthetic resins, epoxy resins and (meth) acrylic resins are particularly preferably used. This is because of its versatility, high transparency, and excellent resistance to color filters.

  The epoxy resin refers to an epoxide containing one or more epoxy groups in the molecule, and in the present invention, a soluble one that is not crosslinked with a curing agent is preferable. Epoxides include bisphenol-type, novolak-type, alkylphenol-type, resorcin-type, polyglycol-type, ester-type, glycidyl type such as N-glycidylamine, and cyclic aliphatic epoxides.

  (Meth) acrylic resin is a copolymer of monomers or mixtures of acrylic acid, methacrylic acid, and esters thereof, and is a copolymer of radically polymerizable monomers such as styrene, vinyl acetate, and maleic anhydride. It may be a coalescence.

  The addition amount of these synthetic resins is not particularly limited, but is preferably 5 to 200 parts by weight with respect to 100 parts by weight of the organic pigment and the like, and if less than 5 parts by weight, the expected effect is poor, and if more than 200 parts by weight, There is a possibility of adverse effects such as impairing the functions of the thermosetting resin, thermoplasticity, photosensitive resin, monomer, oligomer, photoinitiator and the like that are finally added as a color filter composition. In addition, the poor compatibility with these additive compositions is conspicuous, and the desired dispersion stabilization may not be exhibited.

  Known kneaders that can be used during salt milling can be used. However, by using a high-speed stirring device or a high-torque kneading device such as a kneader, the pigment can be easily refined and high-speed processing is possible. It becomes.

<Preparation of hydrous paste>
After the above-mentioned refinement process is completed, the magma is taken out, poured into water, stirred and dispersed, filtered and washed to remove the water-soluble inorganic salt. Thus, the micronized pigment composition of the present invention can be obtained as a pigment water paste.

  At this time, the pigment water paste preferably has a fine pigment concentration of 10 to 70% by weight, more preferably 20 to 50% by weight. When the pigment concentration is within this range, the pigment water paste is easy to handle due to the solids such as other resins contained as components, and even in the subsequent solvent phase inversion process, the kneadability and water separation properties are reduced due to the mechanical force. This is advantageous.

<Solvent phase inversion>
The pigment water paste containing the micronized pigment obtained as described above is directly dried, pulverized, and further subjected to a dispersion process. For example, a pigment dispersion for a color filter is obtained by conventional sorbet salt milling. It exhibits better dispersibility than finer pigments and improves the performance as a color filter. In the present invention, for the purpose of significant labor saving and easy dispersion, which is one of the further problems, the manufacturing method for carrying out solvent phase inversion without drying the pigment water paste and preparing the dispersion composition as it is is carried out extremely effectively. be able to.

  That is, a pigment water paste containing a finer pigment obtained as described above and a water-insoluble solvent are charged into a flasher, flushed with a water-insoluble solvent, the phase of the pigment is changed from an aqueous phase to an oil phase, By decanting and removing, a pigment dispersion can be produced. By this method, since it is not subjected to a strong dispersion treatment step, and the pigment is included and treated with the dispersant in a finely dispersed state and does not cause strong agglomeration in the drying step, the fineness of the cohesiveness is lower. A dispersion of fluorinated pigment can be obtained. Moreover, since a strong dispersion process and a drying process are not required, a large amount of energy is not required.

  In addition, when flushing with a water-insoluble solvent, in addition to the solvent (flushing solvent), some of the dispersants and resins used in salt milling are water-insoluble and soluble in the flushing solvent. It is also possible to add. That is, some or all of them can be used together during flushing as long as the dispersion stabilizing composition during salt milling is not impaired.

  Furthermore, it is preferable that the pigment dispersion is distilled under reduced pressure to remove the remaining water to 1.0% by weight or less in the final pigment dispersion. If the remaining amount is larger than this, for example, the film forming property of the final color filter and other necessary characteristics may be adversely affected.

  As the solvent used in this solvent phase inversion step, the water-based paste of the micronized pigment composition of the present invention can be phase-inverted to the solvent paste, and used as a solvent for the final final pigment dispersion, or after phase inversion, It is necessary to select from those that can be replaced with the final dispersion solvent (that is, it can be removed by distillation in a subsequent step), and take into consideration various dispersants, resins, additives, and the like.

  The solvent must be a water-insoluble solvent. For example, when preparing a pigment dispersion for a color filter, an alcohol solvent (limited to a water-insoluble solvent), a ketone solvent, an ester Examples thereof include an aliphatic solvent, an aliphatic hydrocarbon solvent, an aromatic hydrocarbon solvent, and an ether solvent.

  Examples of the alcohol solvent include n-butanol, sec-butanol, tert-butanol, n-pentanol, n-hexanol, n-heptyl alcohol, n-octyl alcohol; ketone solvents include methyl ethyl ketone and methyl isobutylkenton. Cyclohexanone; as ester solvents, ethyl acetate, n-butyl acetate, ethyl lactate, methyl ethoxypropionate, ethyl ethoxypropionate; as aliphatic hydrocarbon solvents, n-pentane, n-hexane, n- Heptane; As aromatic hydrocarbon solvents, toluene, o-xylene, m-xylene, p-xylene, mesitylene; As ether solvents, ethyl cellosolve acetate, butyl cellosolve acetate, 1-methoxy-2-propyl acetate, Tylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol diacetate, propylene glycol diacetate, 3-methoxy Examples thereof include butyl acetate and 3-methoxy-3-methylbutyl acetate. These solvents may be used alone or in combination of two or more. The ether solvent is also a solvent used when preparing the pigment dispersion.

  Depending on the pigment type, the water paste after salt milling may be flushed with toluene and the like, and then the toluene may be removed and replaced with a dispersion solvent to obtain a desired pigment dispersion.

  Further, as the flasher, a known one can be used, and examples thereof include a kneader, a sand grinder mill, and the like, and other apparatuses can be used as long as the phase can be changed from the aqueous phase to the solvent phase. Well, it is not limited at all.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples for use as a color filter, but the present invention is not limited to the following examples.

(Example 1)
<Refining process>
150 g of ε-type copper phthalocyanine pigment (CI Pigment Blue 15: 6 (may be abbreviated as P.B.15: 6), Toyo Ink Mfg. Co., Ltd., “Lionol Blue E”), neutral Anhydrous sodium sulfate (average particle diameter of about 20 μm, manufactured by Mitajiri Chemical Industry Co., Ltd.) 3038 g, pigment derivative (manufactured by Nippon Lubrizol Co., Ltd., “pigment derivative dispersant Solsperse 5000”) 16.5 g (10 weight in pigment) %), Polymer dispersant (Ajinomoto Finetech Co., Ltd., “Ajisper PB821F”) 83.3 g (50% by weight of pigment), acrylic resin (Shin Nakamura Chemical Co., Ltd., “Banaresin PSY-C1 33.3 g (converted to solid content, 20% by weight of pigment), propylene glycol monomethyl ether acetate (hereinafter abbreviated as PMA) as a dispersion stabilizing solvent. 584 g of “Arcosolve PMA” manufactured by Chemical Co., Ltd. is added to a double-arm kneader (hereinafter referred to as “kneader”, manufactured by Moriyama Co., Ltd., 5 L kneader Σ type), and the temperature of the kneaded material in the kneader is 50 ° C. The mixture was kneaded for 10 hours while controlling the temperature (hereinafter, the kneaded product is referred to as magma). Thus, the miniaturization process is completed.

  In the above composition, neutral anhydrous sodium sulfate is not included, and the concentration is adjusted to a pigment content of 10% by weight using PMA, and separately prepared by dispersion with a paint conditioner (hereinafter sometimes referred to as PC). From the results of haze and viscosity measurement of the dispersion (hereinafter abbreviated as PC-B-1) obtained in this way, it means the viscosity at low haze and low viscosity (shear rate of 10 [1 / s]. And the TI value is 1.5 or less, it was confirmed in advance that the composition was a dispersion-stable system. These confirmation methods are as described later.

<Preparation of hydrous paste>
The magma after the refinement process was taken out, stirred and dispersed in 30 L of warm water at 40 ° C., then transferred to Nutsche, filtered, and washed with water until the mirabilite was completely removed. The pigment water paste, which is a finer pigment composition containing a large amount of water washed, had a pigment concentration of 30.6% by weight.

<Solvent phase inversion (flushing)>
425 g of pigment water paste (solid content 52% by weight) after micronization (equivalent to 130 g of pure pigment) is put into a 1 L kneader (manufactured by Moriyama Co., Ltd., Σ type), and the jacket temperature is 35 ° C. While stirring, the solvent PMA 70g was added and kneaded for 30 minutes. Thereafter, the separated water was removed by decantation to obtain a paste of finer pigment mainly containing PMA. Next, PMA was further added to dilute the pigment concentration to about 12% by weight, and the remaining water was dehydrated to 1.0% or less by distillation at 60 ° C. under reduced pressure. At this stage, a pigment dispersion having a pigment concentration of about 14% by weight was obtained.

<Preparation of pigment dispersion>
Next, 2.6 g of pure pigment was weighed from the obtained pigment dispersion, put into a 70 mL glass bottle, and PMA was added so that the pigment concentration was 13 wt% with respect to the total composition. It was.
80 g of 0.5 mmφ zirconia beads were added and dispersed with PC to remove the zirconia beads to obtain a pigment dispersion. The dispersions for 5 minutes and 60 minutes were used as dispersions for color filter evaluation described later. The pigment dispersion after 5 minutes of dispersion is called CF1-1, and the pigment dispersion after 60 minutes of dispersion is called CF1-2.

Here, the reason for evaluating the two samples as the PC dispersion time is as follows.
As described above, one of the problems of the present invention is to reduce the production cost by significant power saving dispersion. In order to confirm the ease of dispersion of the fine pigment composition of the present invention, solvent phase inversion is performed. A dispersion in which the dispersion time of PC was 5 minutes was prepared as a type in which a slight dispersion force was applied to the pigment dispersion having undergone the above (hereinafter sometimes referred to as PC 5 minutes). On the other hand, a dispersion with sufficient dispersion energy, that is, a dispersion in which the dispersion time of PC is 60 minutes was used for confirmation of reaching quality (hereinafter sometimes referred to as PC 60 minutes). The smaller the difference between the two characteristic values, the easier it was to disperse.

  The dispersion with a PC dispersion time of 60 minutes is a standard method for preparing a pigment dispersion in a laboratory. Therefore, a pigment dispersion of 60 minutes using a powder pigment as a raw material was used in this example and Adopted as a reference (standard) for the comparative example.

(Example 2)
As the dispersion stabilizer in the micronization step of ε type copper phthalocyanine pigment, except using ethyl diglycol acetate (EDGAC) (manufactured by Daicel Chemical Industries, Ltd.) in place of PMA, in the same manner as in Example 1 Two types of pigment dispersions for CF evaluation that were subjected to a solvent phase inversion process were obtained. The pigment dispersion after 5 minutes of dispersion is referred to as CF2-1 and that after 60 minutes of dispersion is referred to as CF2-2.

  In addition, a dispersion obtained by separately preparing a dispersion (hereinafter referred to as PC) in a system in which neutral anhydrous sodium sulfate is not included in the composition in the micronization step, and the concentration is adjusted to a pigment content of 10% by weight using EDGAC. -B-2.) From the results of the haze and viscosity measurement of (B-2), it was confirmed in advance that the composition was a dispersion-stable composition because of the low haze and low viscosity and the TI value of 1.5 or less. These confirmation methods are as described later.

(Comparative Example 1)
Solvent transfer was performed in the same manner as in Example 1 except that 610 g of ethylene glycol (EG) (manufactured by Nippon Shokubai Co., Ltd.) was used instead of PMA 584 g as the solvent in the refinement process of the ε-type copper phthalocyanine pigment. Two types of dispersions for CF evaluation that were subjected to a phase process were obtained. The pigment dispersion after 5 minutes of dispersion is referred to as CF3-1 and that after 60 minutes of dispersion is referred to as CF3-2.

  In addition, a dispersion obtained by separately preparing with a PC (hereinafter referred to as PC-B) in a system in which neutral anhydrous sodium sulfate is not included in the composition in the micronization step and the concentration is adjusted to a pigment content of 10% using EG. -3)), it was confirmed in advance that the composition was color-separated and could not be dispersed at all. These confirmation methods are as described later.

(Comparative Example 2)
<Refining process>
150 g of ε-type copper phthalocyanine pigment (CI Pigment Blue 15: 6, manufactured by Toyo Ink Mfg. Co., Ltd., “Lionol Blue E”), neutral anhydrous sodium sulfate (average particle diameter of about 20 μm, Mitajiri Chemical Industry Co., Ltd.) 3038 g) Ethylene glycol (EG) 590 g as a solvent was added to a 5 L kneader, and kneaded for 10 hours while controlling the temperature of the kneaded product to 70 ° C. Thus, the miniaturization process is completed.

  In addition, a dispersion obtained by separately preparing and dispersing with PC (hereinafter referred to as PC-B-4) in a system in which neutral anhydrous sodium sulfate is not included in the composition in the micronization step, and the concentration is adjusted to a pigment content of 10% with EG. From the results of haze and viscosity measurement, it was confirmed in advance that the composition was color-separated and could not be dispersed at all. These confirmation methods are as described later.

  The magma after the refinement process was taken out, stirred and dispersed in 30 L of warm water at 40 ° C., then transferred to Nutsche, filtered, and washed repeatedly until the mirabilite was completely removed to obtain a pigment water paste.

  The pigment water paste after washing with water was taken out, taken on a drying shelf (material, SUS304), transferred to a dryer, and dried at 105 ° C. for 20 hours (the dried fined pigment is referred to as a drying block). The dried block was pulverized with a pulverizer (manufactured by Kyoritsu Riko Co., Ltd., small pulverizer, sample mill SK-M2). This was used as a finer pigment for color filters.

<Dispersion preparation>
In a 70 mL glass bottle, 2.6 parts of the micronized pigment obtained were weighed. Further, Solsperse 5000 was 10% by weight in the pigment, Azisper PB821F was 50% by weight of the pigment, and Vanaresin PSY-C1 in terms of solid content. The solvent PMA was added so that the pigment concentration was 13% by weight based on the total composition.

  80 g of 0.5 mmφ zirconia beads were added and dispersed with PC to remove the zirconia beads to obtain two dispersions for CF evaluation. The pigment dispersion after 5 minutes of dispersion is called CF4-1, and the pigment dispersion after 60 minutes of dispersion is called CF4-2.

(Example 3)
<Refining process>
Yellow pigment (CI Pigment Yellow 150 (may be abbreviated as PY 150), LANXESS, yellow E4GN-GT) 18 g, neutral anhydrous sodium sulfate (average particle size of about 20 μm, Mitajiri Chemical Industry) (Manufactured by Co., Ltd.) 360 g, polymer dispersant (manufactured by Kawaken Fine Chemical Co., Ltd., “Hinoact T-8000”) 14 g (70% by weight of pigment), yellow pigment derivative (manufactured by Sanyo Dye Co., Ltd., Japanese Patent Application 2007) -305680 derivative) 3 g (14% by weight in pigment), acrylic resin (manufactured by Shin-Nakamura Chemical Co., Ltd., “Vanaresin PSY-C1”) 6 g (in terms of solid content, 30% by weight of pigment), As a dispersion stabilizing solvent, 134 g of PMA was added to a laboratory sand grinder mill (manufactured by Sanyo Pigment Co., Ltd., hereinafter abbreviated as SGM), and the temperature of the kneaded material in SGM was 30 ° C. The mixture was kneaded and ground for 2 hours while controlling the temperature. Thus, the miniaturization process is completed.

  In the above composition, neutral anhydrous sodium sulfate is not included, and a dispersion obtained by separately preparing and dispersing with PC (hereinafter referred to as PC-Y-1) in a system in which the concentration is adjusted to 10% by weight with PMA. From the results of haze and viscosity measurement), the dispersion stable composition was confirmed in advance because of the low haze and low viscosity and the TI value of 1.5 or less. These confirmation methods are as described later.

<Preparation of hydrous paste>
The magma after the refinement process was taken out, stirred and dispersed in 5 L of warm water at 40 ° C., then transferred to Nutsche, filtered, and washed repeatedly until the mirabilite was completely removed to obtain a pigment water paste. The pigment water paste, which is a finer pigment composition containing a large amount of water washed, has a pigment concentration of 21.3% by weight.

<Solvent phase inversion>
45 g of fine pigment water paste (solid content 41.4% by weight) (equivalent to 9.5 g of pure pigment) is put into an automatic mortar for experiment, and 18 g of solvent PMA is added while stirring and kneaded for 10 minutes. did. Thereafter, the separated water was removed by decantation to obtain a paste of finer pigment mainly containing PMA.

  Next, PMA was added to dilute the pigment concentration to about 9% by weight, and the remaining water was dehydrated to 1.0% or less by vacuum distillation at 60 ° C. At this stage, a pigment dispersion having a pigment concentration of about 11% by weight was obtained.

<Dispersion preparation>
Next, 2 g of the pigment dispersion was weighed from the obtained pigment dispersion, put in a 70 mL glass bottle, and PMA was added so that the pigment concentration was 8 wt% with respect to the total composition. 80 g of 0.5 mmφ zirconia beads were added and dispersed with PC to remove the zirconia beads to obtain two dispersions for CF evaluation. The pigment dispersion after 5 minutes of dispersion is referred to as CF5-1 and that after 60 minutes of dispersion is referred to as CF5-2.

(Comparative Example 3)
<Refining process>
320 g of yellow pigment (CI Pigment Yellow 150, manufactured by LANXESS, yellow E4GN-GT), neutral anhydrous sodium sulfate (average particle size of about 20 μm, manufactured by Mitajiri Chemical Co., Ltd.), ethylene glycol (EG) as a solvent 820 g (manufactured by Nippon Shokubai Co., Ltd.) was added to a 5 L kneader, and the temperature was controlled so that the temperature of the kneaded product was 50 ° C., followed by kneading and grinding for 10 hours. Thus, the miniaturization process is completed.

  In the above composition, neutral anhydrous sodium sulfate is not included, and a dispersion obtained by separately preparing a dispersion with PC (hereinafter referred to as PC-Y-2) is a system in which the concentration is adjusted to a pigment content of 10% using EG. (Abbreviated)), it was confirmed in advance that the composition was color-separated and could not be dispersed at all. These confirmation methods are as described later.

  The magma after the refinement process was taken out, stirred and dispersed in 30 L of warm water at 40 ° C., then transferred to Nutsche, filtered, and washed repeatedly until the mirabilite was completely removed to obtain a pigment water paste.

  The pigment water paste after washing with water was taken out, taken on a drying shelf (material, SUS304), transferred to a dryer, and dried at 105 ° C. for 20 hours (the dried fined pigment is referred to as a drying block). The dried block was pulverized with a pulverizer (manufactured by Kyoritsu Riko Co., Ltd., small pulverizer, sample mill SK-M2).

<Dispersion preparation>
Weighing 1.8 g of the refined pigment obtained in a 70 mL glass bottle, and further adding 70% by weight of Hinoact T-8000 to the pigment in terms of solid content, yellow pigment derivative (manufactured by Sanyo Dye Co., Ltd., patent application) Derivatives described in 2007-305680) and pigment (14% by weight) and acrylic resin (Vanaresin PSY-C1) are added to 30% by weight in the pigment, resulting in a pigment concentration of 8% by weight based on the total composition. PMA was added as follows.

  80 g of 0.5 mmφ zirconia beads were added and dispersed with PC to remove zirconia peas to obtain two types of dispersions for CF evaluation. The pigment dispersion after 5 minutes of dispersion is called CF6-1, and the pigment dispersion after 60 minutes of dispersion is called CF6-2.

Example 4
<Refining process>
Red pigment (CI Pigment Red 254 (may be abbreviated as PR 254)), Ciba, Irgahoe Red BT-CF (18 g), neutral anhydrous sodium sulfate (average particle size of about 20 μm, Mitajiri 360 g of Chemical Industry Co., Ltd., 10 g of polymer dispersant (Ajinomoto Finetech Co., Ltd., “Ajisper PB821F”) (50% by weight of pigment), red pigment derivative (manufactured by Sanyo Dye Co., Ltd.), JP2007 -166881) 2 g (10% by weight in pigment), PMA 170 g as a dispersion stabilizing solvent was added to SGM, and the temperature of the kneaded material in SGM was controlled to 30 ° C. for 2 hours. Kneaded and ground. Thus, the miniaturization process is completed.

  In the above composition, neutral anhydrous sodium sulfate was not included, and a dispersion obtained by separately preparing and dispersing with PC (hereinafter referred to as PC-R-1) in a system adjusted to a pigment content of 10% using PMA. Abbreviated).) From the results of haze and viscosity measurement, it was confirmed in advance that the composition was a dispersion-stable composition because it had a low haze and a low viscosity and a TI value of 1.5 or less. These confirmation methods are as described later.

<Preparation of hydrous paste>
The magma after the refinement process was taken out, stirred and dispersed in 5 L of warm water at 40 ° C., then transferred to Nutsche, filtered, and washed repeatedly until the mirabilite was completely removed to obtain a pigment water paste. The pigment water paste, which is a finer pigment composition containing a large amount of water washed, has a pigment concentration of 25.0% by weight.

<Solvent phase inversion (flushing)>
60 g of fine pigment water paste (solid content: 37.3% by weight) (corresponding to a pure pigment content of 15 g) was put into an automatic mortar for experiments, and 15 g of solvent PMA was added and kneaded for 5 minutes while stirring. Thereafter, the separated water was removed by decantation to obtain a paste of finer pigment mainly containing PMA.

  Next, PMA was added to dilute the pigment concentration to about 12% by weight, and the remaining water was dehydrated to 1.0% or less by vacuum distillation at 60 ° C. At this stage, a pigment dispersion having a pigment concentration of about 14% by weight was obtained.

<Dispersion preparation>
Next, 3.0 g of pure pigment was weighed from the obtained pigment dispersion, put into a 70 mL glass bottle, and PMA was added so that the pigment concentration was 12% by weight based on the total composition. It was. 100 g of 0.3 mmφ zirconia beads were added and dispersed with PC to remove the zirconia beads to obtain two dispersions for CF evaluation. The pigment dispersion after 5 minutes of dispersion is referred to as CF7-1, and the dispersion after 60 minutes of dispersion is referred to as CF7-2.

(Comparative Example 4)
<Refining process>
Red pigment (CI Pigment Red 254, manufactured by Ciba, Irgaphore Red BT-CF) 320 g, neutral anhydrous sodium sulfate (average particle size of about 20 μm, manufactured by Mitajiri Chemical Co., Ltd.) 3200 g, diethylene glycol (DEG as a solvent) 690 g (manufactured by Nippon Shokubai Co., Ltd.) was added to a 5 L kneader and kneaded and milled for 9 hours while controlling the temperature of the kneaded product to 50 ° C. Thus, the miniaturization process is completed.

  In the above composition, neutral anhydrous sodium sulfate is not included, and a dispersion obtained by separately preparing and dispersing with PC (hereinafter referred to as PC-R-2) is a system in which the concentration of pigment is adjusted to 10% using DEG. (Abbreviated)), it was confirmed in advance that the composition had no fluidity and had a very high haze and could not be dispersed. These confirmation methods are as described later.

  The magma after the refinement process was taken out, stirred and dispersed in 30 L of warm water at 40 ° C., then transferred to Nutsche, filtered, and washed repeatedly until the mirabilite was completely removed to obtain a pigment water paste.

  The pigment water paste after washing with water was taken out, taken on a drying shelf (material, SUS304), transferred to a dryer, and dried at 105 ° C. for 20 hours (the dried fined pigment is referred to as a drying block). The dried block was pulverized with a pulverizer (manufactured by Kyoritsu Riko Co., Ltd., small pulverizer, sample mill SK-M2).

<Dispersion preparation>
Weighed 2.6 g of the refined pigment obtained in a 70 mL glass bottle, and added a polymer dispersant (Ajinomoto Finetech Co., Ltd., “Azisper PB821F”) to 50% by weight of the pigment. Then, a red pigment derivative (manufactured by Sanyo Dye Co., Ltd., a derivative described in JP 2007-186681 A) is added so as to be 10% by weight in the pigment, and the pigment concentration is 13% by weight with respect to the total composition. PMA was added so that

  After adding 100 g of 0.3 mmφ zirconia beads and dispersing with PC, the zirconia beads were removed to obtain two dispersions for CF evaluation. The pigment dispersion after 5 minutes of dispersion is called CF8-1, and the pigment dispersion after 60 minutes of dispersion is called CF8-2.

(Evaluation of dispersion for confirming dispersion stability)
<Preparation of dispersion for confirming dispersion stability>
≪P. B. Preparation of 15: 6 dispersion stable composition confirmation dispersion >>
[Preparation of PC-B-1]
In a 35 mL glass bottle, 0.9 g of Lionol Blue E, 0.1 g of Solsperse 5000 (10% by weight in the pigment), 0.5 g of Ajisper PB821F, 8.5 g of PMA as a solvent, The pigment content was added to 10% by weight. After adding 40 g of 0.5 mmφ zirconia beads and carrying out a dispersion treatment with PC for 60 minutes, the zirconia beads were removed to obtain a dispersion for confirming the dispersion stability composition, PC-B-1. The pigment component includes Lionol Blue E and Solsperse 5000.

[Preparation of PC-B-2, PC-B-3]
PC-B-2 and PC-B-3 were respectively prepared in the same manner as the preparation of PC-B-1, except that EDGAC and EG were used instead of PMA, respectively.

[Preparation of PC-B-4]
To a 35 mL glass bottle, 0.9 g of Lionol Blue E and 8.1 g of EG as a solvent were added, and the pigment content in the composition was 10% by weight. Furthermore, after adding 40 g of 0.5 mmφ zirconia beads and carrying out a dispersion treatment with PC for 60 minutes, the zirconia beads were removed to obtain a dispersion for confirming dispersion stability composition PC-B-4.

≪P. Y. Preparation of 150 dispersion stable composition confirmation dispersion >>
[Preparation of PC-Y-1]
In a 35 mL glass bottle, 0.9 g of yellow E4GN-GT, 0.1 g of yellow pigment derivative (10% by weight in the pigment), 0.5 g of Hinoact T-8000, 0.15 g of vanaresin PSY-C1 (Conversion to solid content, 15% by weight of pigment), 8.35 g of PMA was added as a solvent, and the pigment content in the composition was 10% by weight. Furthermore, after adding 40 g of 0.5 mmφ zirconia beads and carrying out a dispersion treatment with PC for 60 minutes, the zirconia beads were removed to obtain a dispersion for confirming the dispersion stability composition, PC-Y-1. The pigment component includes yellow E4GN-GT and a yellow pigment derivative.

[Preparation of PC-Y-2]
To a 35 mL glass bottle, 0.9 g of yellow E4GN-GT and 8.1 g of EG as a solvent were added, so that the pigment content in the composition was 10% by weight. Furthermore, after adding 40 g of 0.5 mmφ zirconia beads and carrying out a dispersion treatment with PC for 60 minutes, the zirconia beads were removed to obtain a dispersion for confirming dispersion stability composition PC-Y-2.

≪P. R. Preparation of dispersion for confirming dispersion stability composition of H.254 >>
[Preparation of PC-R-1]
In a 35 mL glass bottle, 0.9 g of Irgahoe Red BT-CF, 0.1 g of red pigment derivative (10% by weight in the pigment), 0.5 g of Hinoact T-8000, and 0.1% of Vanaresin PSY-C1. 30 g (converted to solid content, 30% by weight of pigment) and 8.2 g of PMA as a solvent were added to make the pigment content in the composition 10% by weight. Furthermore, after adding 40 g of 0.5 mmφ zirconia beads and carrying out a dispersion treatment with PC for 60 minutes, the zirconia beads were removed to obtain PC-R-1 which is a dispersion for confirming dispersion stability. The pigment component includes irgaphore red BT-CF and a red pigment derivative.

[Preparation of PC-R-2]
To a 35 mL glass bottle, 0.9 g of Irgahoe Red BT-CF and 8.1 g of DEG as a solvent were added, so that the pigment content in the composition was 10% by weight. Furthermore, after adding 40 g of 0.5 mmφ zirconia beads and carrying out a dispersion treatment with PC for 60 minutes, the zirconia beads were removed to obtain a dispersion for confirming the dispersion stability composition, PC-R-2.

<Measurement of physical properties of dispersion for confirmation of dispersion stability>
For each of the dispersions for confirming the dispersion stability composition thus obtained, the viscosity when the shear rate is 10 [1 / s] and the viscosity when the shear rate is 100 [1 / s] are determined by a viscometer (TV-22 viscometer, Toki TI value was calculated.
Moreover, each said dispersion was developed on PET film using the bar coater (Bar coater No. 6 (0.5 mm)), and it dried at 80 degreeC, and created the coating film. The haze of the obtained coating film was measured with a haze meter (NDH 2000, manufactured by Nippon Denshoku Industries Co., Ltd.).
Table 1 shows the measurement results of the viscosity and haze and the calculation results of the TI value. In Table 1, the notation that measurement is impossible is due to the fact that the pigment and the solvent were completely separated from each other and a dispersion could not be obtained.

(Evaluation of Examples and Comparative Examples)
<Measurement of primary particle diameter of pigment by transmission electron microscope>
The primary particle size of the refined pigment contained in the pigment dispersions obtained in Examples 1 to 4 and Comparative Examples 1 to 4 was measured using a transmission electron microscope (manufactured by JEOL Ltd., JEM-1011 transmission electron microscope). Then, arbitrary particles were visually selected from an image of 60,000 times, and the vertical and horizontal dimensions were measured based on the measurement scale described in the image. In the 60,000 times image, the outline of the particle is not always clear, so that the error is taken into account and the outline is described. The measurement results are shown in Table 2.

<Measurement of dispersion properties and production of color filter for contrast evaluation>
For the dispersions (CF1-1 to CF8-2) obtained in Examples 1 to 4 and Comparative Examples 1 to 4, the viscosity at a shear rate of 10 [1 / s] and the viscosity at 100 [1 / s] The viscosity of was measured with a viscoelasticity measuring device (“Physica MCR-1000” manufactured by Anton Paar). The measurement results are shown in Tables 3 and 4.

  Further, a spin coating liquid (hereinafter referred to as SPC liquid) was prepared using each dispersion for measuring the contrast ratio. A binder resin (manufactured by Shin-Nakamura Chemical Co., Ltd., Vanaresin PSY-C1) was added so that the solid content other than the pigment in the SPC solution was 1: 1 with respect to the pigment. The SPC solution was individually applied to a glass plate having a thickness of 1 mm and a square of 100 mm with a spin coater (manufactured by Mikasa Co., Ltd., spin coater MS-150A) at three rotation speeds, and 90 ° C. in an air bath It was dried for 5 minutes (about pre-baking). Thus, three glass coating plates were produced for each sample.

<Measurement of contrast>
Subsequently, the three glass coated plates after the pre-baking step were measured with a spectrocolorimeter (manufactured by Konica Minolta Sensing Co., Ltd., spectrocolorimeter CM-3700d).
Next, the luminance of the glass coating plate was measured with a color luminance meter (LS-100, manufactured by Konica Minolta Sensing Co., Ltd.). A polarizing plate was placed on the backlight, and the spacing between the polarizing plate and the glass coating plate was set to 1 mm. After confirming that the luminance of the backlight was sufficiently stable, the luminance of the glass coated plate was measured. The luminance was measured by adjusting the polarizing plate to the crossed Nicol position, then rotated 90 °, and the luminance was measured at the parallel position. The Yxy chromaticity and each luminance are analyzed using analysis software at a certain chromaticity position. Based on the measured contrast value of the standard product, the relative ratio of the contrast of CF produced using the pigment dispersion of the present invention to be evaluated was determined and compared. The results are shown in Tables 3 and 4. In Examples 1 and 2 and Comparative Examples 1 and 2, CF4-2 is a standard product, in Examples 3 and 3, CF6-2 is a standard product, and in Examples 4 and 4, CF8- 2 was a standard product. These standard products are pigment dispersions produced by a conventional production method.

As shown in Table 2, it can be seen that the refined pigment composition of the present invention has a primary particle size of 10 nm or less. Further, as shown in Tables 3 and 4, the pigment dispersion obtained by the production method of the present invention has a viscosity / contrast relative ratio of 60 minutes after dispersion time (PC 60 minutes) and after 5 minutes (PC 5 minutes). ) Can be grasped, but the conventional manufacturing method cannot be grasped except for Comparative Example 1, and it can be seen that a very stable dispersion state is formed. In particular, regarding the relative ratio of contrast (PC 60 minutes), it can be seen that the dispersion obtained by the production method of the present invention is excellent as a color filter.
Further, in each of the examples and comparative examples, although there is a difference in each evaluation item between PC 5 minutes and PC 60 minutes, a dispersible material that can be evaluated with PC 5 minutes is not obtained at all as in the comparative example according to the conventional manufacturing method. On the other hand, it can be seen that labor-saving production is possible in the examples, as an evaluationable dispersion is obtained.

According to the method for producing a micronized pigment composition and a pigment dispersion of the present invention, a micronized pigment composition containing an extremely micronized micronized pigment can be easily provided, and a drying process and the like are performed. Therefore, it can be used for the preparation of the pigment dispersion in the state of the pigment water paste, so that the pigment dispersion excellent in the dispersion stability of the finely divided pigment can be provided with low power, that is, at low cost without reaggregation. .
Therefore, the present invention can be widely used for pigment dispersions obtained using solvent-based dispersions, and are used in color filters, inkjet inks, and other fields that require particularly excellent light transmittance or high coloring power. For example, it is extremely useful in applications where a finely dispersed finely dispersed pigment is required.

Claims (6)

A dispersion-stabilized pigment composition comprising an organic pigment, a dispersion-stabilizing solvent and a dispersant, and a mixture containing a water-soluble inorganic salt are kneaded and ground, then washed and dehydrated to obtain a refined pigment composition. A dispersion phase- stabilizing pigment composition comprising: a step of adding a solvent to the finely divided pigment composition and a solvent in a flasher; a phase inversion of the pigment from an aqueous phase to an oil phase ; A pigment dispersion characterized in that the product satisfies the following conditions, and the dispersion stabilizing solvent and dispersant contained in the mixture in the refinement step are the same as the solvent and dispersant used in the solvent phase inversion step Body manufacturing method.
Dispersion-stabilized pigment composition: For a dispersion-stabilized pigment composition having a pigment concentration of about 5 to 20% by weight, the viscosity at a shear rate of 10 [1 / sec] and 100 [1 / sec] is measured with a rheometer. The viscosity when the shear rate is 10 [1 / sec] is 100 [mPa · s] or less, and the TI value = (viscosity when 10 [1 / sec]) / (100 [1 / sec]. ] Is 1.5 or less.   The method for producing a pigment dispersion according to claim 1, wherein the dispersion stabilizing solvent is an alkylene glycol lower alkyl ether acetate.   The method for producing a pigment dispersion according to claim 2, wherein the alkylene glycol lower alkyl ether acetate is at least one selected from propylene glycol monomethyl ether acetate (PMA) and ethyl diglycol acetate (EDGAC).   The method for producing a pigment dispersion according to claim 1, wherein in the solvent phase inversion step, water is decanted and removed, and then distilled under reduced pressure.   The method for producing a pigment dispersion according to claim 1, wherein the residual water content in the pigment dispersion is reduced to 1.0 wt% or less by distillation under reduced pressure.   The method for producing a pigment dispersion according to claim 1, wherein the organic pigment contains an organic pigment derivative.