JP2022081518A - Pigment dispersion liquid for color filters, coloring composition for color filters, color filters and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pigment dispersion liquid for color filters capable of excellently dispersing a pigment and excellent in development characteristics during color filter manufacturing.

SOLUTION: A pigment dispersion liquid for color filters contains an organic pigment, a dispersant and a solvent, in which a total mass of Ca and Fe, and a total mass of Mg, Al and Cr are less than or equal to a specified mass ppm, and the dispersant is a basic block copolymer containing an A block containing a structural unit represented by a general formula (1) and a B block containing a structural unit derived from a carboxy group-containing monomer.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a pigment dispersion for a color filter, and more specifically, a pigment dispersion for a color filter in which the total content of a specific metal element is defined, a coloring composition for a color filter containing the pigment dispersion, and a coloring composition for a color filter. It relates to the color filter obtained by using.

A color filter used for a display or the like generally has a transparent substrate, a colored layer, a light-shielding portion, and the like, and examples of the method for forming the colored layer include a pigment dispersion method, a dyeing method, an electrodeposition method, and a printing method. However, among them, the pigment dispersion method is widely used in terms of spectral characteristics, durability, pattern shape, accuracy, and the like (Patent Documents 1 and 2).

In recent years, with the development of displays, the demand for liquid crystal displays, organic EL displays, etc. has increased, and along with this, the performance of these displays has been improved by improving color playability, contrast, luminance, color reproducibility, etc. Is strongly desired.

Furthermore, in recent years, in order to improve the definition of tablets, smartphones, etc., the black matrix has become thinner, and the phenomenon of parallax mixing, in which the colors of adjacent pixels appear to be mixed when viewed from the side, has become a particular problem. ..
In order to solve the problem, it is required to reduce the film thickness of the color filter, and specifically, for example, it is required to achieve a film thickness of about 50% to 70% of the conventional film thickness.
On the other hand, as for the reproduction color of the pixel, high color performance in the chromaticity range defined as "adobe RGB standard" and "DCI standard"("DCI" is Digital Cinema Initiatives) is required.

Therefore, in order to reduce the film thickness of the color filter and increase the color rendering of the pixels, it is necessary to increase the pigment concentration of the coloring composition for the color filter.

However, when trying to increase the pigment concentration of the coloring composition for a color filter and the pigment dispersion liquid used therein, it may be difficult to disperse the pigment satisfactorily in the first place.
Further, if the pigment dispersion used for preparing the coloring composition for a color filter is a pigment dispersion having a viscosity higher than a constant viscosity, the viscosity of the coloring composition is high and coating is difficult, or the stability over time is high. It cannot be practically used because it may not be obtained. As a result, there is a problem that the pigment concentration of the pigment dispersion liquid or the coloring composition for a color filter cannot be increased.

That is, even if a color filter that satisfies the above-mentioned color performance and the like can be designed, a pigment dispersion having a viscosity higher than a constant viscosity cannot be used. Therefore, even if the pigment concentration is high, the viscosity becomes low after dispersion. A pigment dispersion that is stable over time is required.

Further, the coloring composition for a color filter has a problem that the development characteristics are deteriorated at the time of manufacturing a color filter due to a high pigment concentration.
That is, in order to increase the color density of the color filter, even if a coloring composition for a color filter having excellent dispersion performance can be obtained even at a high density, it is difficult to achieve both the development characteristics at the time of manufacturing the color filter. Was also occurring.

On the other hand, Patent Documents 3 to 6 are known as those that specify the content of metal elements in a color filter or a coloring composition for producing a color filter.

Patent Document 3 defines the total amount of sodium ion (Na ⁺ ) and potassium ion (K ⁺ ) contained in the pixels of R (red), G (green), B (blue) and BK (black). As a result, a technique for preventing contamination of a liquid crystal element or a semiconductor element close to a color filter is disclosed.
Patent Document 4 discloses a technique for achieving high shading rate and low surface reflectance by defining the total amount of sodium (Na) and potassium (K) in a resin coated with carbon black for black matrix. Has been done.

Patent Document 5 describes a pigment dispersion liquid in which the electric conductivity is specified and the contents of sodium (Na), potassium (K), and magnesium (Mg) are specified, and the pigment dispersion liquid is used. The color filter thus obtained is said to have good display stability because it has an excellent voltage retention rate.
In Patent Document 6, C.I. I. An organic pigment composition for a color filter in which the contents of sodium ion (Na ⁺ ), potassium ion (K ⁺ ), and magnesium ion (Mg ⁺ ) contained in Pigment Green 58 are specified is described, and the organic pigment composition for a color filter is described. The color filter thus obtained is said to have excellent display responsiveness.

However, since the pigment dispersion liquid for a color filter for a display requires extremely high dispersion, the above-mentioned technique is not yet sufficient, and further improvement is desired in order to solve the above-mentioned problems. rice field.
In particular, due to higher definition, disparity color mixing has become a problem, and high pixel color performance has been required. In recent years, there has been a demand for lower film thickness of color filters, and various pigment dispersion stability. A pigment dispersion or a coloring composition for a color filter, which has excellent performance in terms of image characteristics, developability at the time of producing a color filter, and the like, has been desired.

Japanese Unexamined Patent Publication No. 2007-133131 Japanese Unexamined Patent Publication No. 2009-244617 Japanese Unexamined Patent Publication No. 7-198928 Japanese Unexamined Patent Publication No. 9-07733 Japanese Unexamined Patent Publication No. 2009-007432 Japanese Unexamined Patent Publication No. 2014-119487

The present invention has been made in view of the above background technology, and the problems thereof are that the film thickness of the color filter is reduced, the difference color mixing when viewed from the side is small, and the reproduction color of the pixel is also a constant color. It is an object of the present invention to provide a pigment dispersion liquid for a color filter, which has excellent characteristics such as achieving high color performance in a degree range.
Further, even if the pigment concentration of the coloring composition for a color filter is increased, the pigment can be dispersed well, and even if the pigment concentration is increased, it does not easily deteriorate over time. Therefore, a pigment dispersion liquid for a color filter having excellent viscosity stability. , And a coloring composition for a color filter using the same.

Further, when a coloring composition for a color filter is produced using a pigment dispersion liquid, the pigment concentration of the coloring composition for a color filter can be increased, and as a result, dispersion performance that realizes a high color density can be obtained, and at the same time, the dispersion performance can be obtained. It is an object of the present invention to provide a coloring composition for a color filter, which can achieve both the "dispersion performance for realizing a high color density" and the development characteristics at the time of manufacturing a color filter.

As a result of diligent research to achieve the above object, the present inventor has extremely described sodium (Na) and potassium (K) contained in the pigment dispersion for a color filter or the coloring composition for a color filter. "Calcium (Ca), iron (Fe), magnesium (Mg), aluminum (Al), chromium (Cr)" which are metal elements other than common metal elements (hereinafter, the inside of this parenthesis is simply referred to as "specific metal element". By reducing the content of (abbreviated)), it has been found that, surprisingly, a pigment dispersion for a color filter, a coloring composition for a color filter, and a color filter can be obtained in which the above-mentioned problems are solved.

In addition, the present inventor, when there is a "specific metal element" mixed from a solvent, process water, an apparatus member, etc. used in the process of producing an organic pigment, disperses the pigment at the time of producing the pigment dispersion liquid. It has been found that the initial viscosity of the liquid becomes high, the stability over time becomes poor, the development time becomes long, and an appropriate pattern and good pixels cannot be obtained.
Then, by reducing the mixing of the "specific metal element" in the organic pigment, the dispersant, and the solvent, which are the raw materials of the pigment dispersion for the color filter (in particular, the "specific metal element" in the organic pigment. The present invention has been completed by finding that a pigment dispersion for a color filter, a coloring composition for a color filter, and a color filter can be obtained by reducing the mixing).

That is, the present invention is a pigment dispersion for a color filter containing an organic pigment, a dispersant and a solvent, and the total mass of calcium (Ca) and iron (Fe) contained in the pigment dispersion for a color filter is determined. It is intended to provide a pigment dispersion liquid for a color filter, characterized in that it is 180 mass ppm or less with respect to the entire pigment dispersion liquid for a color filter.

Further, in the present invention, the total mass of magnesium (Mg), aluminum (Al) and chromium (Cr) contained in the color filter pigment dispersion is 140 mass ppm or less with respect to the entire color filter pigment dispersion. The above-mentioned dispersant is a basic block copolymer containing an A block containing a structural unit represented by the general formula (1) described later and a B block containing a structural unit derived from a carboxy group-containing monomer. It provides a pigment dispersion liquid for a color filter.

Further, the present invention is a coloring composition containing the above-mentioned pigment dispersion for a color filter, a polymerization initiator and an alkali-soluble resin, and is the total of calcium (Ca) and iron (Fe) contained in the coloring composition. The mass is 120 mass ppm or less with respect to the entire coloring composition, and the total mass of magnesium (Mg), aluminum (Al) and chromium (Cr) contained in the coloring composition is the coloring composition. It is an object of the present invention to provide a coloring composition for a color filter, which is characterized in that it is 60% by mass or less with respect to the whole.

The present invention also provides a color filter characterized by having a colored layer which is a cured product of the colored composition for a color filter containing the above-mentioned pigment dispersion for a color filter.

The present invention also provides a display device having the above-mentioned color filter.

As described above, it is possible to prevent contamination of liquid crystal elements and semiconductor elements close to the color filter by avoiding the mixing of extremely common metal elements such as sodium (Na) and potassium (K), and to prevent the metal in the pigment coating resin. The content of the metal is specified to achieve high shading rate and low surface reflectance, and the content of the metal in the color filter is specified to increase the voltage retention rate to improve display stability and display responsiveness. The technology is known.
That is, there are known techniques for reducing common metal elements and improving specific optical and electrical properties that are directly caused by the inclusion of the metal.

However, by specifying a specific metal element, at the stage of the pigment dispersion liquid, its aspect (high concentration, etc.) and physical properties (low viscosity, dispersion stability, etc.) were improved, and it was finally excellent using it. The technique for obtaining color filters is unknown.

That is, by defining the content of metal elements such as calcium (Ca) and iron (Fe), the content of metal elements such as magnesium (Mg), aluminum (Al), and chromium (Cr) can be further specified. It is known that a pigment dispersion liquid with excellent dispersion stability can be obtained with low viscosity (appropriate viscosity) even at a high pigment concentration, and as a result, a color filter with excellent image characteristics and development characteristics can be obtained. Not done.

According to the present invention, there is provided a pigment dispersion for a color filter that can solve the above-mentioned problems and problems and can disperse well even if the concentration of the pigment contained in the pigment dispersion for a color filter is increased, and is not easily deteriorated with time. be able to.

Further, when a coloring composition for a color filter is produced using the pigment dispersion for a color filter of the present invention, the pigment concentration in the coloring composition for a color filter can be increased, and as a result, the film thickness is low. It is possible to obtain a color filter that realizes a high color density.
Further, by using the pigment dispersion liquid for a color filter of the present invention, it is possible to provide a coloring composition for a color filter which can obtain good dispersion performance and dispersion stability performance and also have good development characteristics at the time of manufacturing a color filter. Can be done.

Particularly in recent years, in order to solve the above-mentioned problems, it is required to reduce the film thickness of the color filter, and on the other hand, the reproduction color of the pixel is also required to have high color performance in a certain chromaticity range. By using a pigment dispersion for a color filter, it is possible to reduce the film thickness of the color filter, achieve low disparity color mixing, achieve high color performance, and provide a coloring composition and a color filter for a color filter having excellent developability in patterning. can do.

Hereinafter, the present invention will be described, but the present invention is not limited to the following specific forms, and can be arbitrarily modified within the scope of the technical idea.

The "pigment dispersion for color filter" of the present invention contains at least an organic pigment, a dispersant and a solvent, and the total mass of calcium (Ca) and iron (Fe) contained in the pigment dispersion for color filter. However, it is characterized in that it is 180 mass ppm or less with respect to the entire pigment dispersion liquid for a color filter.
Further, the "coloring composition for a color filter" of the present invention is a coloring composition containing the above pigment dispersion, a polymerization initiator and an alkali-soluble resin, and the calcium (Ca) contained in the coloring composition. It is characterized in that the total mass of iron (Fe) and iron (Fe) is 120 mass ppm or less with respect to the entire coloring composition.
In the present invention, the "pigment dispersion for a color filter" may be simply abbreviated as a "pigment dispersion", and the "coloring composition for a color filter" may be simply abbreviated as a "coloring composition".

<Organic pigment>
The organic pigment used in the present invention is a coloring pigment including an achromatic color such as black, and is not particularly limited as long as it can develop a desired color as an organic pigment for a color filter. Here, "for the color filter" includes all for coloring the color filter, such as for the pixel portion and the black matrix portion.
Hereinafter, "organic pigment" may be simply abbreviated as "pigment".

Further, as the organic pigment used in the present invention, a lake pigment that can be dispersed by binding various substituents to a dye or insolubilizing it in a solvent by using a known rake formation (chlorination) method. Can also be mentioned.

Here, the organic pigments include achromatic pigments such as white, black, and gray, and specifically, blue pigments, green pigments, red pigments, yellow pigments, purple pigments, orange pigments, brown pigments, and black pigments. Pigments of various colors such as pigments can be used.
Since the pigment dispersion liquid of the present invention is used as a color filter material, it is mainly a blue pigment, a green pigment, a red pigment, and a black pigment. Is also used.
Among the above, blue pigments, green pigments, red pigments, yellow pigments, purple pigments and the like are preferable from the viewpoint of exhibiting the above-mentioned effects of the present invention.

Specific examples of organic pigments are shown below by pigment number. The following "CI" means a color index.

As the red pigment, C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 37, 38, 41, 47, 48, 48: 1, 48: 2, 48: 3, 48: 4, 49, 49: 1, 49: 2, 50: 1, 52: 1, 52: 2, 53, 53: 1, 53: 2, 53: 3, 57, 57: 1, 57: 2, 58: 4, 60, 63, 63: 1, 63: 2, 64, 64: 1, 68, 69, 81, 81: 1, 81: 2, 81: 3, 81: 4, 83, 88, 90: 1, 101, 101: 1, 104, 108, 108: 1, 109, 112, 113, 114, 122, 123, 144, 146, 147, 149, 151, 166, 168, 169, 170, 172, 173, 174, 175, 176, 177, 178, 179, 181, 184, 185, 187, 188, 190, 193, 194, 200, 202, 206, 207, 208, 209, 210, 214, 216, 220, 221, 224, 230, 231, 232, 233, 235, 236, 237, 238, 239, 242, 243, 245, 247, 249, 250, 251, 253, 254, 255, 256, 257, 258, 259, 260, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276 and the like.
Among these, preferably, C.I. I. Pigment Red 48: 1, 122, 168, 177, 202, 206, 207, 209, 224, 242, 254 and the like, and C.I. I. Pigment Red 177, 209, 224, 254 and the like.

As the blue pigment, C.I. I. Pigment Blue 1, 1: 2, 9, 14, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 17, 19, 25, 27, 28, 29, 33, Examples thereof include 35, 36, 56, 56: 1, 60, 61, 61: 1, 62, 63, 66, 67, 68, 71, 72, 73, 74, 75, 76, 78, 79 and the like.
Among these, preferably, C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, etc. are mentioned, and C.I. I. Pigment Blue 15: 6 and the like.

Examples of the green pigment include C.I. I. Pigment Greens 1, 2, 4, 7, 8, 10, 13, 14, 15, 17, 18, 19, 26, 36, 45, 48, 50, 51, 54, 55, 58, 59 and the like.
Among these, preferably, C.I. I. Pigment greens 7, 36, 58, 59 and the like.

As the yellow pigment, C.I. I. Pigment Yellow 1, 1: 1, 2, 3, 4, 5, 6, 9, 10, 12, 13, 14, 16, 17, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1,37,37: 1,40,41,42,43,48,53,55,61,62,62: 1,63,65,73,74,75,81,83,87,93,94, 95, 97, 100, 101, 104, 105, 108, 109, 110, 111, 116, 117, 119, 120, 126, 127, 127: 1, 128, 129, 133, 134, 136, 138, 139, 142, 147, 148, 150, 151, 153, 154, 155, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 172, 173, 174, 175, 176, 180, 181, 182, 183, 184, 185, 188, 189, 190, 191, 191: 1, 192, 193, 194, 195, 196, 197, 198, 199, 200, 202, 203, 204, 205, 206, 207, 208, 213 and the like can be mentioned.
Among these, preferably C.I. I. Pigment Yellow 83, 117, 129, 138, 139, 150, 154, 155, 180, 185, 213 and the like, and C.I. I. Pigment Yellow 83, 138, 139, 150, 180, 185 and the like.

As the orange pigment, C.I. I. Pigment Orange 1, 2, 5, 13, 16, 17, 19, 20, 21, 22, 23, 24, 34, 36, 38, 39, 43, 46, 48, 49, 61, 62, 64, 65, Examples thereof include 67, 68, 69, 70, 71, 72, 73, 74, 75, 77, 78 and 79.
Among these, preferably, C.I. I. Pigment Orange 38, 71 and the like.

As the purple pigment, C.I. I. Pigment Violet 1, 1: 1, 2, 2: 2, 3, 3: 1, 3: 3, 5, 5: 1, 14, 15, 16, 19, 23, 25, 27, 29, 31, 32, 37, 39, 42, 44, 47, 49, 50 and the like can be mentioned.
Among these, preferably C.I. I. Pigment Violet 19, 23 and the like, and particularly preferably C.I. I. Pigment Violet 23 and the like.

In the present invention, one kind of the above pigment may be used, or two or more kinds of the above pigments may be used.
Further, when the pigment dispersion liquid of the present invention is a pigment dispersion liquid for a black matrix of a color filter, a black pigment can be used as an organic pigment.
Examples of the black pigment include carbon black. That is, in the present invention, carbon black is also included in the organic pigment.
Further, the achromatic organic pigment such as black may be the achromatic pigment alone or may be mixed with a coloring pigment such as red, green or blue.

Preferred organic pigments in the present invention are anthraquinone pigments such as Pigment Red 177; diketopyrrolopyrrole pigments such as Pigment Red 254; and azomethine pigments such as Pigment Yellow 150 from the viewpoint of chemical structure and light transmission spectrum. Azo pigments such as; quinophthalone pigments such as Pigment Yellow 138; dioxazine pigments such as Pigment Violet 23; phthalocyanine pigments such as Pigment Blue 15: 6; benzimidazolone pigments such as Pigment Yellow 180; quinoxalin pigments such as Pigment Yellow 213; quinacridone. Pigments; isoindolin pigments; isoindolinone pigments; indanslen pigments; perylene pigments; and the like.

In particular, from the viewpoint of exhibiting the effect of the present invention, the organic pigment is one or more organic pigments selected from the group consisting of anthraquinone pigments, diketopyrrolopyrrole pigments, azo pigments, quinophthalone pigments, dioxane pigments and phthalocyanine pigments. It is particularly preferable to have.

In the present invention, one kind or two or more kinds of organic pigments having the same chemical structure skeleton, that is, the same system may be used in the system. Further, two or more types may be used across the system. Further, it may be a mixed crystal.

Since the organic pigment having the above-mentioned chemical structure is often used as an organic pigment for a color filter, a pigment dispersion liquid having a high concentration is often required, and the dispersibility and developability of a specific metal element can be improved. Since the influence is large and the specific metal element is likely to be mixed in the manufacturing process, the above-mentioned effect of the present invention is particularly easy to be exerted.
Specifically, for example, Pigment Red 254, Pigment Red 177, Pigment Yellow 150, Pigment Yellow 185, Pigment Yellow 138, Pigment Yellow 139, Pigment Blue 15: 6, Pigment Violet 23, Pigment Green 58 or Pigment Green 59 are described above. Especially preferred for reasons.

Further, the dye used as a raw material for the dispersible lake pigment can be appropriately selected from conventionally known dyes. Examples of such dyes include azo dyes, metal complex salt azo dyes, anthraquinone dyes, triphenylmethane dyes, xanthene dyes, cyanine dyes, naphthoquinone dyes, quinoneimine dyes, methine dyes, and phthalocyanine dyes.
As a guide, if the amount of the lake pigment dissolved in 10 g of the solvent (or the mixed solvent) is 10 mg or less, the lake pigment (dye) can be dispersed in the solvent (or the mixed solvent). It can be determined.

<< Acidic dye derivative >>
It is preferable that the organic pigment in the present invention contains an acidic dye derivative because the above-mentioned effect of the present invention can be easily exerted. When an acidic dye derivative is used, fine dispersion is possible, and when used for a color filter, the dispersion stability is high, the contrast is high, the light transmittance is high, the brightness is high, and the pigment is dispersed. It is preferable because a liquid can be obtained.
Further, when the acidic dye derivative is used, the effect of reducing the specific metal element in the present invention is more exerted, and the above effect can be synergistically exerted.

Here, the "acidic dye derivative" refers to a dye derivative having an acidic group in its chemical structure, and is particularly preferably composed of an anthraquinone pigment, diketopyrrolopyrrole pigment, azo pigment, quinophthalone pigment, dioxazine pigment and phthalocyanine pigment. A pigment derivative having one or more pigment skeletons selected from the group and having an acidic group.
Among the acidic dye derivatives, the quinophthalone pigment derivative, which has a pigment skeleton of a quinophthalone pigment and is a dye derivative having an acidic group, is more preferable in terms of improving dispersibility.

As the acidic group of the pigment derivative, at least one selected from the group consisting of a sulfo group, a sulfonamide group, a carboxy group, and a metal salt or an ammonium salt of the functional group is preferable.
The average amount of acidic groups introduced into one molecule of the pigment is not particularly limited, but is preferably 0.5 to 5, more preferably 0.6 to 4, and 0.7 to 3.5. Especially preferable.
The introduction of an acidic group enables fine dispersion, and when used for a color filter, a pigment dispersion liquid having high dispersion stability, high contrast, high light transmittance, and high brightness can be obtained. Therefore, by reducing the specific metal element, a synergistic effect can be obtained and the effect can be further obtained.

The organic pigment in the present invention preferably contains a pigment and an acidic dye derivative. The acidic dye derivative interacts with the pigment and is adsorbed or incorporated on the surface of the pigment when the pigment particles are produced.
Further, by adsorbing on the surface of the pigment, it acidifies the surface of the pigment and acts as an intermediary with the pigment dispersant, which enhances the affinity with the pigment dispersant rather than the organic pigment itself.
Further, the acidic dye derivative that interacts with the basic dispersant is adsorbed on the pigment surface, so that the basic dispersant can be efficiently positioned on the pigment surface. This enables fine dispersion and dispersion stabilization, which is excellent when used for color filters.

The content of the acidic dye derivative in the whole organic pigment in the present invention is not particularly limited, but is preferably 0.5 to 30 parts by mass and 1 to 15 parts by mass with respect to 100 parts by mass of the pigment. Is more preferable, and 2 to 10 parts by mass is particularly preferable.
By setting it to the above lower limit value or more, stable dispersion and fine dispersion are possible, and a synergistic effect with the above-mentioned reduction of the specific metal element is obtained. Can be suppressed.

In the present invention, as the organic pigment, one kind or two or more kinds of the above acidic dye derivatives may be used, and one kind or two or more kinds of the above acidic dye derivatives may be used for one kind of pigment. good.

The acidic dye derivative may be added to the dispersion of the pigment particles at any stage, but in consideration of adsorbing or incorporating the acidic dye derivative on the surface of the pigment, a step of producing the pigment. It can also be added to pigments in It can be added during the process, during the dispersal process, during the post-dispersion process, and the like.
It can be added to a good solvent or a poor solvent in the reprecipitation method, or it can be added after the pigment particles are precipitated or when they are concentrated or redispersed thereafter.

According to the present invention, further, the dispersant is a (salt-type) basic block-type dispersant or a (salt-type) basic graft-type dispersant, which will be described later, so that the salt-forming site thereof is a pigment and particularly. The main chain and side chains of the polymer dispersant, which have strong adsorptivity to acidic dye derivatives adsorbed on the pigment surface and have affinity for solvents, improve the dispersibility of the pigment dispersion for color filters. As a result, the concentration of the organic pigment can be increased, the viscosity can be reduced, the change over time of the pigment dispersion can be suppressed, and as a result, the developability is improved in the evaluation of the coloring composition for a color filter.

<< Pigment particle size >>
The particle size of the organic pigment is not particularly limited, but is preferably 30 nm to 500 nm, more preferably 40 nm to 300 nm, and particularly preferably 50 nm to 200 nm.
If the particle size is too small, the dispersibility and resolubility are lowered, and the workability may be lowered due to contamination by fine powder and the like.
On the other hand, if the particle size is too large, the dispersibility, dispersion stability, light resistance, etc. deteriorate, and the effect of reducing the content of specific metals such as calcium (Ca) and iron (Fe) becomes difficult to appear. The effect of the invention is not exhibited, and in particular, good contrast cannot be obtained.

Here, "re-dissolvability" refers to the property that the solid content of the coloring composition for a color filter once dried is dissolved again in the solvent. For example, if a coloring composition for a color filter adheres to the tip of a die lip during coating with a die coater, a solidified product is generated by drying, but when the coating is resumed, the solidified product dissolves in the colored composition for a color filter. If it is not easy, the solidified substance on the die lip is partially peeled off and easily adheres to the colored layer of the color filter, which causes foreign matter defects.

<Dispersant>
As the dispersant in the present invention, a known dispersant can be appropriately selected and used, and for example, a cationic, anionic, nonionic, amphoteric, silicone-based, fluorine-based or other surfactant; polymer. Dispersant; A low molecular weight dispersant or the like can be used. Above all, a polymer dispersant (including a polymer surfactant) is preferable because it can be dispersed uniformly and finely.

Examples of the polymer dispersant include polymer dispersants such as modified polyurethane, modified polyacrylate, modified polyester, and modified polyamide.
Specifically, (co) polymers of "unsaturated carboxylic acid esters such as (meth) acrylic acid esters"; (partial) of "(co) polymers of unsaturated carboxylic acids such as (meth) acrylic acid". ) Amine salt, (partially) ammonium salt or (partially) alkylamine salt; (co) polymer of "unsaturated carboxylic acid ester such as (meth) acrylic acid ester having a primary, secondary or tertiary amino group" , (Partial) salt of the amino group of the (co) polymer, (partial) acid modified product of the amino group of the (co) polymer; (Co) polymers of "esters" and their modifications; polyurethanes; unsaturated polyamides; polysiloxanes; long-chain polyaminoamide phosphates; by reaction of poly (lower alkyleneimine) with free carboxy group-containing polyesters. The obtained amides and salts thereof; and the like can be mentioned.

<< Polymer Dispersant and Small Molecule Dispersant >>
The "dispersant" in the present invention is not particularly limited, and a known polymer dispersant or small molecule dispersant can be used for dispersing the pigment.

Examples of the polymer dispersant include a random dispersant composed of a random (co) polymer; a block dispersant composed of a block copolymer; a pendant as a side chain in places with respect to the main chain (like a branch). ) A graft-type dispersant made of a graft (co) polymer or the like to which a repeating unit is bonded; and the like.
Further, a salt-type dispersant in which at least a part of the constituent units of the (co) polymer has a salt structure is also preferable. Such a salt type applies to all of the above random type dispersants, block type dispersants and graft type dispersants, and they are preferably used.

Examples of the polymer dispersant include (co) polymers of unsaturated carboxylic acid esters such as poly (meth) acrylic acid esters; and (co) polymers of unsaturated carboxylic acids such as poly (meth) acrylic acid. (Partial) amine salts, (partial) ammonium salts and (partial) alkylamine salts; (co) polymers of hydroxyl group-containing unsaturated carboxylic acid esters such as hydroxyl group-containing poly (meth) acrylic acid esters and their modifications; polyurethanes Unsaturated polyamides; Polysiloxanes; Long-chain polyaminoamide phosphates; Amidos obtained by the reaction of poly (lower alkyleneimine) with free carboxy group-containing polyesters, salts thereof, and polyester groups on the side chains ( Examples thereof include a copolymer of a meta) acrylate.

Among them, poly (meth) acrylate, sodium maleate-olefin copolymer, terminal carboxy group-containing polyester (for example, Japanese Patent Publication No. 54-34009); tetrakis (2-hydroxyalkyl) ethylenediamine is used as a starting material. Polyester having an acidic group and / or a basic group (Japanese Patent Laid-Open No. 2-245231, etc.); (Japanese Patent Laid-Open No. 8-259876, etc.); A copolymer obtained by copolymerizing a macromonomer (an oligomer having a polymerizable unsaturated group at one end) and a monomer having a nitrogen atom (Japanese Patent Laid-Open No. 8). 10-339949 (Ab. 10-339949, etc.)) and the like are preferable.

Examples of the low molecular weight dispersant include an anionic compound having a sulfonic acid group, a carboxylic acid group and the like; a cationic compound having an aliphatic amine salt, a quaternary ammonium salt and the like; a nonionic compound having a hydroxyl group, an oxyethylene chain and the like. Sex compounds; polymer compounds; and the like.
Specific examples thereof include sorbitan fatty acid ester, polyoxyethylene alkylamine, alkyldiamine, and alkanolamine derivative (US Pat. No. 3,536,510).

Among the dispersants, the polymer dispersant is preferable, and among the polymer dispersants, the basic block type dispersant and / or the basic graft type dispersant are functionally separated from the pigment adsorption site and the solvent affinity site. In addition to the "total content of calcium (Ca) and iron (Fe)" and "total content of calcium (Ca) and iron (Fe)" described later, magnesium (Mg) and aluminum (Al) are further added. By setting the "total content of chromium (Cr)" to a certain value or less, there is a synergistic effect with the above-mentioned effects of the present invention such as dispersion stability, colored image quality, and developability, and the combination with the above-mentioned acidic dye derivative is used. It is preferable because it has a synergistic effect when it is used.

Here, "the dispersant is a basic block type dispersant and / or a basic graft type dispersant" means that the dispersant is a basic block type dispersant, and is a basic graft type dispersant. Whether it is a basic block-type dispersant and a basic graft-type dispersant in combination, or a dispersant that is both a basic block-type dispersant and a basic graft-type dispersant at the same time. Also means. Moreover, the combined use of a dispersant that is neither a basic block type dispersant nor a basic graft type dispersant is not excluded.

<< Basic block type dispersant >>
The "basic block type dispersant" is a monomer having a basic group such as an amino group, a monoalkylamino group, a dialkylamino group, an amide group; a salt thereof; a trialkylammonium group; and the like (hereinafter, "a monomer"). (Abbreviated as) and a dispersant composed of a block copolymer of another monomer different from the monomer (hereinafter, abbreviated as “b monomer”), which may be a binary copolymer or a ternary or more. It may be a copolymer. The "a monomer" also includes those in which the above "alkyl" is paraphrased as "aryl", "aralkyl", "alkenyl" and the like.

Examples of the a monomer include a (meth) acrylate compound containing a secondary or tertiary amino group or a salt thereof in which a quaternary ammonium base and / or hydrogen bonded to nitrogen may be substituted with a substituent. Preferred, particularly preferred, are tertiary amino groups and / or quaternary ammonium bases.

［一般式（１）中、Ｒ^１は水素原子又はメチル基、Ａは２価の連結基、Ｒ^２及びＲ^３は、それぞれ独立して、水素原子又はヘテロ原子を含んでもよい炭化水素基を表し、Ｒ^２及びＲ^３が互いに結合して環構造を形成してもよい。］ As the a monomer, a monomer having a structural unit represented by the following general formula (1) or a salt type of the structural unit represented by the following general formula (1) (described later) is more preferable. That is, in the present invention, the pigment dispersion for a color filter, wherein the dispersant is a basic block copolymer containing a structural unit represented by the following general formula (1) or a salt thereof, is preferable.

[In the general formula (1), R ¹ is a hydrogen atom or a methyl group, A is a divalent linking group, and R ² and R ³ are each independently a hydrocarbon group which may contain a hydrogen atom or a hetero atom. Represented, R ² and R ³ may be bonded to each other to form a ring structure. ]

Specifically, the salt is formed by salting a tertiary amino group such as a unit forming a basic block copolymer with an acid such as a sulfonic acid compound or a phosphoric acid compound. Can be mentioned.
In addition, a tertiary amino group such as dimethylaminoethyl (meth) acrylate, which is a unit for forming a basic block copolymer, may be converted into a quaternary ammonium salt by an aryl halide, an aralkyl halide or the like.

When the a monomer gives a repeating unit represented by the general formula (1), a compound that reacts with an amino group after appropriately copolymerizing with another polymerizable monomer, for example, a sulfonic acid compound or phosphorus. Acid compounds such as acid compounds and carboxylic acid compounds; halogen compounds such as aryl halides, alkyl halides, and aralkyl halides; and the like may be reacted to partially or wholly form a quaternary ammonium salt.

Examples of the sulfonic acid compound include compounds represented by the following general formula (2). That is, as the salt-formed compound, the block copolymer is a compound represented by the following general formula (2) in which at least a part of the nitrogen of the structural unit represented by the above general formula (1) becomes a cation. The above-mentioned pigment dispersion for a color filter, which is a salt-type block copolymer in which one or more compounds selected from the above group serve as anions and form salts thereof, is preferable.

［一般式（２）において、Ｒ^ａは、炭素数１～２０の直鎖、分岐鎖若しくは環状のアルキル基；置換基を有してもよいビニル基、フェニル基若しくはベンジル基又は－Ｏ－Ｒ^ｅを表し、Ｒ^ｅは、炭素数１～２０の直鎖、分岐鎖若しくは環状のアルキル基；置換基を有してもよいビニル基、フェニル基若しくはベンジル基；又は炭素数１～４のアルキレン基を介した（メタ）アクリロイル基を表す。］

[In the general formula (2), Ra is ^a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms; a vinyl group which may have a substituent, a phenyl group or a benzyl group or —R. Re represents ^e , where ^Re is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms; a vinyl group which may have a substituent, a phenyl group or a benzyl group; or an alkylene having 1 to 4 carbon atoms. Represents a (meth) acryloyl group via a group. ]

Examples of the above-mentioned "halogen compounds such as aryl halides, alkyl halides, and aralkyl halides" include compounds represented by the following general formula (3). That is, as the salt-formed compound, the block copolymer is a compound represented by the following general formula (3) in which at least a part of the nitrogen of the structural unit represented by the above general formula (1) becomes a cation. The above-mentioned pigment dispersion for a color filter, which is a salt-type block copolymer in which one or more compounds selected from the above group serve as anions and form salts thereof, is preferable.

［一般式（３）において、Ｒ^ｂ、Ｒ^ｂ’及びＲ^ｂ”は、それぞれ独立に、水素原子；酸性基若しくはそのエステル基；置換基を有してもよい炭素数１～２０の、直鎖、分岐鎖若しくは環状のアルキル基；置換基を有してもよいビニル基、フェニル基若しくはベンジル基；又は－Ｏ－Ｒ^ｆを表し、Ｒ^ｆは、置換基を有してもよい、炭素数１～２０の直鎖、分岐鎖若しくは環状のアルキル基；置換基を有してもよい、ビニル基、フェニル基若しくはベンジル基；又は炭素数１～４のアルキレン基を介した（メタ）アクリロイル基を表し、Ｘは、塩素原子、臭素原子又はヨウ素原子を表す。］
一般式（３）中のＸが、カウンターアニオン（Ｘ^－）となり塩を形成する。

[In the general formula (3), R ^b , R ^b'and R ^{b "} are independent of each other and have a hydrogen atom; an acidic group or an ester group thereof; a direct group having 1 to 20 carbon atoms which may have a substituent. A chain, branched or cyclic alkyl group; a vinyl group which may have a substituent, a phenyl group or a benzyl group; or —OR ^{f, where R f may} have a substituent, carbon. A linear, branched or cyclic alkyl group of number 1-20; optionally having a substituent, a vinyl group, a phenyl group or a benzyl group; or a (meth) acryloyl mediated by an alkylene group of 1-4 carbon atoms. Represents a group, where X represents a chlorine atom, a bromine atom or an iodine atom.]
X in the general formula (3) becomes a counter anion (X ⁻ ) and forms a salt.

Examples of the phosphoric acid compound include compounds represented by the following general formula (4). That is, as the salt-formed compound, the block copolymer is a compound represented by the following general formula (4) in which at least a part of the nitrogen of the structural unit represented by the above general formula (1) becomes a cation. The above-mentioned pigment dispersion for a color filter, which is a salt-type block copolymer in which one or more compounds selected from the above group serve as anions and form salts thereof, is preferable.

［一般式（４）において、Ｒ^ｃ及びＲ^ｄは、それぞれ独立に、水素原子；水酸基；炭素数１～２０の、直鎖、分岐鎖若しくは環状のアルキル基；置換基を有してもよい、ビニル基、フェニル基若しくはベンジル基；又は－Ｏ－Ｒ^ｅを表し、Ｒ^ｅは、炭素数１～２０の、直鎖、分岐鎖若しくは環状のアルキル基；置換基を有してもよい、ビニル基、フェニル基若しくはベンジル基；又は炭素数１～４のアルキレン基を介した（メタ）アクリロイル基を表す。ただし、Ｒ^ｃ及びＲ^ｄの少なくとも１つは炭素原子を含む。］

[In the general formula (4), R ^c and R ^d may each independently have a hydrogen atom; a hydroxyl group; a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms; and a substituent. , Vinyl group, phenyl group or benzyl group; or —O—R ^e ; ^Re may have a linear, branched or cyclic alkyl group with 1 to 20 carbon atoms; a substituent. It represents a vinyl group, a phenyl group or a benzyl group; or a (meth) acryloyl group via an alkylene group having 1 to 4 carbon atoms. However, at least one of R ^c and R ^d contains a carbon atom. ]

Specific examples of the a monomer include a dialkylaminoalkyl ester of (meth) acrylic acid, a diallylaminoalkyl ester of (meth) acrylic acid, a dialalkylaminoalkyl ester of (meth) acrylic acid, and (meth) acrylic acid. Dialkenylaminoalkyl esters of the above, salts thereof and the like can be mentioned. Examples of the compound used for forming "these salts" include compounds represented by the above general formulas (2) to (4).

More specifically, for example, a tertiary amino group-containing compound such as dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylate; these tertiary aminos. Salts of group-containing compounds; amides such as N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, etc. Classes; quaternary ammonium group-containing compounds such as (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyltriethylammonium chloride, (meth) acryloyloxyethylbenzyldimethylammonium chloride. Salt; etc.

Particularly preferred are dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate sulfonate, dimethylaminoethyl (meth) acrylate phenylphosphonate, (meth) acryloyloxyethyl benzyl dimethylammonium chloride and the like. Be done.

When the basic block copolymer in which the a monomer is (co) polymerized or a salt-type dispersant thereof is used for a color filter, fine dispersion and dispersion stabilization become possible, and the pigment concentration is increased. Can also maintain good dispersion stability. That is, it is possible to increase the concentration of the pigment dispersion liquid and the coloring composition, and to make the color filter obtained by using the pigment dispersion liquid and the coloring composition highly color-developed, thinned, high-contrast, good-developable, good-redissolvable, etc. Due to the synergistic effect of limiting the content of the above-mentioned, the above-mentioned effect of the present invention is likely to be exhibited.

The organic pigment is firmly adsorbed to the nitrogen moiety contained in the a monomer (preferably the structural unit represented by the general formula (1)) to have excellent pigment dispersibility, and is firmly adsorbed to the nitrogen moiety. The organic pigment surrounded by the dispersant is easily washed away while being adsorbed on the dispersant during development, the organic pigment is not left behind on the substrate, and the generation of residue is easily suppressed.
Similarly, the organic pigment that is firmly adsorbed on the nitrogen moiety and surrounded by the dispersant is easily washed away while being adsorbed on the dispersant by the resoluble solvent.

Examples of the b-monomer include acrylates such as benzyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate and phenoxyethyl (meth) acrylate; and styrenes such as styrene as aromatic group-containing monomers. Vinyl ethers such as phenylvinyl ether; and the like.
Furthermore, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic. Examples thereof include (meth) acrylic acid ester-based monomers such as 2-ethylhexyl acid, glycidyl (meth) acrylate, and hydroxyethyl (meth) acrylate; vinyl acetate; acrylonitrile; and allyl group-containing compounds such as allyl alkyl ether.

As the b-monomer, a carboxy group-containing monomer is also preferable. The carboxy group-containing monomer refers to a monomer containing a copolymerizable unsaturated double bond and a carboxy group.
Examples of the carboxy group-containing monomer include (meth) acrylic acid, vinyl benzoic acid, maleic acid, maleic acid monoalkyl ester, fumaric acid, itaconic acid, crotonic acid, cinnamic acid, and (meth) acrylic acid dimer. ..
Further, an addition reaction product of a monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and a cyclic anhydride such as maleic anhydride, phthalic anhydride, or cyclohexanedicarboxylic acid anhydride; ω-carboxy-. Polycaprolactone mono (meth) acrylate and the like can also be mentioned.
Moreover, as a precursor of the carboxy group, a carboxy group-containing monomer using an acid anhydride such as maleic anhydride, itaconic anhydride, and citraconic anhydride can also be mentioned.
Among them, (meth) acrylic acid is particularly preferable from the viewpoint of copolymerizability, cost, solubility and the like.

The comprehensive reason for selecting the b-monomer is that it has an affinity for a solvent and enables fine dispersion and dispersion stabilization, especially when used for a color filter.

Assuming that the polymerization block containing a monomer or a salt thereof is "A" and the polymerization block containing b monomer is "B", the basic block type dispersant in the present invention is an AB block copolymer, A-. Any of a BA block copolymer, a BAB block copolymer, an ABAB block copolymer, and a block copolymer of more than that may be used, but the AB block is preferable. It is a copolymer.

In a block copolymer containing a monomer or a salt thereof, the block portion containing the a monomer or its salt is adsorbed on the organic pigment, and the block portion not containing the a monomer or its salt has an affinity for the solvent. , The dispersibility of the organic pigment can be improved.

The weight average molecular weight (Mw) of the basic block copolymer in the present invention is not particularly limited, but is preferably in the range of 500 to 100,000, more preferably in the range of 1,000 to 30,000, and 3,000. It is particularly preferably in the range of 20,000 to 20,000, most preferably 4000 to 15,000.
Within the above range, it is possible to achieve both "wetting property for uniformly dispersing the pigment" and dispersion stability. Further, when the pigment dispersant of the present application is used as a component of the coloring composition, when the upper limit is not more than the above value, the viscosity of the dispersion liquid does not become too high, and the developability and the resolvability do not deteriorate. When the lower limit is equal to or higher than the above value, sufficient dispersibility can be obtained.

Here, the weight average molecular weight (Mw) is determined by gel permeation chromatography (GPC) as a standard polystyrene-equivalent value.
The weight average molecular weight (Mw) of the basic block copolymer was measured using HLC-8120GPC manufactured by Toso Co., Ltd., and N-methylpyrrolidone containing 0.01 mol / L lithium bromide as an elution solvent. The polystyrene standards for calibration curves are Mw377400, 210500, 96000, 50400, 20650, 10850, 5460, 2930, 1300, 580 (above, Easi PS-2 series manufactured by Polymer Laboratories) and Mw1090000 (manufactured by Toso Co., Ltd.). , The measurement column was TSK-GEL ALPHA-M x 2 (manufactured by Toso Co., Ltd.).

The amine value is not particularly limited, but is preferably 15 to 200 mgKOH / g, more preferably 30 to 150 mgKOH / g, and particularly preferably 40 to 130 mgKOH / g.
If the amine value is too small, sufficient dispersion stability cannot be obtained, and if it is too large, the solubility in a solvent decreases.
The amine value can be determined by JIS-K7237.

The acid value is preferably 0 to 50 mgKOH / g, more preferably 1 to 30 mgKOH / g, and particularly preferably 2 to 18 mgKOH / g. Within this range, the development characteristics are excellent. Further, if the acid value is larger than the above upper limit, "resist pattern peeling" may easily occur.

When the molecular weight, amine value or acid value is in the above range, it is easy to disperse, good dispersion stability can be maintained even if the pigment concentration is increased, developability is good, and the metal content is limited. The above-mentioned effect of the present invention is easily exhibited by the synergistic effect.
As a result, the color display obtained by using the pigment dispersion liquid becomes a display having high contrast, high light transmittance, and high brightness.

<< Basic graft type dispersant >>
The "basic graft-type dispersant" refers to a basic dispersant composed of a (co) polymer in which a repeating unit is bonded to a main chain as a side chain.
Specifically, a side chain is synthesized first and then (co) polymerized, that is, a macromonomer having a polymerization unsaturated group at one end (repeatedly having a polymerizable unsaturated group at one end). Examples thereof include a dispersant made of a (co) polymer containing an oligomer having a unit as a polymerization component.
In addition, a dispersant consisting of a (co) polymer in which a main chain is first synthesized and then a repeating unit (like a branch) is bonded to a pendant as a side chain in places with respect to the main chain is used. Can be mentioned.

The basicity of the "basic graft-type dispersant" may be imparted in any way, but it is preferable that the basicity is imparted by copolymerizing a nitrogen atom-containing monomer having basicity.
The basic monomer to be copolymerized is not particularly limited, and specific examples thereof include the "a monomer" described in the section of the "basic block type dispersant".

The "macromonomer having a polymerizable group unsaturated group at one end" is not particularly limited, and known ones can be used.
The polymerization component constituting the repeating unit in the macromonomer is not particularly limited, but specifically, for example, a styrene-based monomer such as styrene or α-methylstyrene; methyl (meth) acrylate, (meth) acrylic. Ethyl acetate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, benzyl (meth) (Meta) acrylic acid ester-based monomers such as (meth) acrylate and hydroxyethyl (meth) acrylate; (meth) acrylamide, N-methylolacrylamide, N, N-dimethylacrylamide, N, N-dimethylaminoethylacrylamide and the like (meth) ) Acrylate-based monomers; vinyl acetate; acryliconitrile; allyl group-containing compounds such as allylalkyl ethers; and the like. The macromonomer in the present invention preferably has a unit in which the above-mentioned polymerization component is polymerized.

In the "basic graft-type dispersant", in addition to the above-mentioned "macromonomer having a polymerizable group unsaturated group at one end" and "basic monomer to be copolymerized", other polymerizable monomers are copolymerized. May be good.
The "other polymerizable monomer" is not particularly limited, and specific examples thereof include the "b monomer" described in the section of the "basic block type dispersant".

The introduction rate of the macromonomer is not particularly limited, but it is preferable that the macromonomer is introduced at an average ratio of 0.1 to 20 in 100 repeating units of the main chain, and 0.3 to 10 are introduced. It is particularly preferable to introduce it in proportion.

The molecular weight of the basic graft-type dispersant in the present invention is not particularly limited, but the polystyrene-equivalent weight average molecular weight (Mw) is usually 1000 to 100,000, preferably 2000 to 40,000, more preferably 3000 to 30,000, and particularly preferably. Is 4000 to 25000, more preferably 5000 to 20000.
Within the above range, it is easy to disperse, and fine dispersion is possible in the "final dispersion step when preparing the pigment dispersion", and the dispersion time can be shortened. As a result, the color display obtained by using the pigment dispersion liquid becomes a display having high contrast, high light transmittance, and high brightness.

<< Commercial product >>
In the present invention, the commercial product used as a dispersant is not limited, and specifically, for example, EFKA-4046, EFKA-4047, EFKA polymer 10, EFKA polymer 400, EFKA polymer 401, EFKA polymer 4300, EFKA Polymer 4310, EFKA Polymer 4320, EFKA Polymer 4330 (above, manufactured by BASF Japan Ltd.), Disperbyk111, Disperbyk161, Disperbyk165, Disperbyk167, Disperbyk167, Disperbyk182, Disperbyk192, DISperbyk2000, DISperbyk2000 SOLSPERSE24000, SOLSPERSE27000, SOLSPERSE28000 (all manufactured by Lubrizol), Azisper (registered trademark) PB821, PB822 (manufactured by Ajinomoto Fine-Techno Co., Ltd.) and the like.

<Solvent>
The pigment dispersion liquid of the present invention contains at least an organic pigment, a dispersant and a solvent, but the solvent is not particularly limited, and known ones are used.

Specifically, for example, alcohols such as methanol, ethanol and propanol; ethers such as tetrahydrofuran; propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol methyl ethyl ether, propylene glycol monoethyl ether, propylene glycol diethyl ether and the like. Dialkylene glycol ethers; Dialkylene glycol ethers such as dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl ethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether; tripropylene glycol monomethyl ether, tri Trialkylene glycol ethers such as propylene glycol dimethyl ether, tripropylene glycol methyl ethyl ether, tripropylene glycol monoethyl ether and tripropylene glycol diethyl ether; alkylene glycol monoalkyl ethers such as propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate. Acetates; Dialkylene glycol monoalkyl ether acetates such as dipropylene glycol monomethyl ether acetate and dipropylene glycol monoethyl ether acetate; Trialkylene glycol monoalkyl ethers such as tripropylene glycol monomethyl ether acetate and tripropylene glycol monoethyl ether acetate. Acetates; Aromatic hydrocarbons such as toluene and xylene; Ketones such as methyl ethyl ketone, methyl propyl ketone, methyl amyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone; ethyl 2-hydroxypropionate, 2 -Methyl hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, butyl 3-methoxyacetate, butyl 3-methyl-3-methoxyacetate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2-hydroxy-2- Methyl methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate and other esters; etc. Can be mentioned.
These solvents may be used alone or in combination of two or more.

Of these, propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethoxyethyl propionic acid, 3-methoxybutyl acetate, 3-methoxy-3-methyl-1-butyl acetate, and methyl 2-hydroxypropanoate are particularly preferable.

<Content ratio>
In the pigment dispersion liquid for a color filter of the present invention, the content ratios of the organic pigment, the dispersant and the solvent are not particularly limited, but the following are preferable.
The dispersant is preferably 5 to 200 parts by mass, more preferably 10 to 150 parts by mass, particularly preferably 15 to 100 parts by mass, and most preferably 20 to 60 parts by mass with respect to 100 parts by mass of the organic pigment.
Further, the organic pigment is preferably 3 to 40 parts by mass, more preferably 5 to 35 parts by mass, and particularly preferably 7 to 30 parts by mass with respect to 100 parts by mass of the pigment dispersion liquid.

With the above-mentioned "content ratio of organic pigment and dispersant", the pigment is easily dispersed, excellent dispersion stability can be obtained, a pigment dispersion liquid having a high pigment concentration can be obtained, and the dispersion time can be shortened. ..
As a result, the color filter obtained by using the pigment dispersion liquid exhibits the above-mentioned effects, enables high color rendering, high contrast, thin film formation, high light transmittance, and a high-luminance display.

Further, the above-mentioned "content ratio of organic pigment and solvent" is excellent in dispersibility, dispersion stability and the like, and is adjusted to a suitable viscosity. In the pigment dispersion liquid of the present invention, at least a polymerization initiator and an alkali-soluble resin are used. (And preferably, when a colored composition is obtained by containing (preferably a polymerizable polyfunctional compound), the content ratio thereof can be easily adjusted to the optimum value, which is preferable.

<Dispersion method>
The above-mentioned organic pigment is dispersed and contained in a solvent in the presence of a dispersant. The effect of the present invention is particularly exhibited when it is wet-dispersed and contained.

In the present invention, the dispersion time is not particularly limited, but 0.01 to 50 hours is preferable, 0.02 to 30 hours is more preferable, and 0.05 to 10 hours is preferable so that the dispersion particle size of the pigment is suitable. Is particularly preferable.

<Metal content in pigment dispersion>
The pigment dispersion for a color filter of the present invention is characterized in that the total mass of calcium (Ca) and iron (Fe) contained in the pigment dispersion is 180 mass ppm or less with respect to the entire pigment dispersion. do.
The total mass of calcium (Ca) and iron (Fe) is preferably as small as possible without considering cost and the like, but specifically, it is preferably 140 mass ppm or less with respect to the entire pigment dispersion. It is more preferably 70 mass ppm or less, particularly preferably 30 mass ppm or less, still more preferably 15 mass ppm or less, and most preferably 5 mass ppm or less.

When the "total mass of calcium (Ca) and iron (Fe) contained in the pigment dispersion" is not more than the above upper limit, it can be dispersed well even if the concentration of the pigment contained in the pigment dispersion is increased, and it can be dispersed over time. A pigment dispersion for a color filter can be obtained, which maintains good stability and does not easily deteriorate over time despite having a high pigment concentration.

Further, when a coloring composition for a color filter is produced using a pigment dispersion having a "total mass of calcium (Ca) and iron (Fe) contained in the pigment dispersion" of not more than the above upper limit, the coloring composition is contained. The pigment density can be increased, and as a result, a color filter that realizes a high color density even with a low film thickness can be obtained.
By using such a pigment dispersion, it is possible to obtain a coloring composition or a color filter which can achieve a low film thickness of a color filter, have less parallax color mixing, achieve high color rendering, and have excellent developability in patterning.

In the coloring composition obtained by using the pigment dispersion having a limited amount of metal, the pigment concentration can be increased, good dispersion performance and dispersion stability can be obtained, and good development characteristics during color filter manufacturing can be achieved. Will be done. That is, for example, the composition in the coloring composition is easily dissolved in the unexposed portion together with the organic pigment in an alkaline developer.

The lower limit of the "total mass of calcium (Ca) and iron (Fe) contained in the pigment dispersion" is not particularly limited, but is preferably 1 mass ppm or more, and particularly preferably 3 mass ppm or more. When it is at least the above lower limit, it is sufficient to improve the dispersibility and the developability, so that the cost required for excessive removal of the metal element is not incurred.

In the pigment dispersion for a color filter of the present invention, the total mass of magnesium (Mg), aluminum (Al) and chromium (Cr) contained in the pigment dispersion is 200 mass ppm with respect to the entire pigment dispersion. The following is preferable.
The total mass of magnesium (Mg), aluminum (Al) and chromium (Cr) contained in the pigment dispersion is more preferably 140 mass ppm or less, particularly preferably 60 mass ppm or less, based on the entire pigment dispersion. More preferably, it is 20 mass ppm or less.

The "total mass of calcium (Ca) and iron (Fe) contained in the pigment dispersion" is equal to or less than the upper limit, and "magnesium (Mg), aluminum (Al) and chromium (Cr) contained in the pigment dispersion". When the "total mass" is not more than the above upper limit, the pigment can be dispersed even better even if the concentration of the pigment contained in the pigment dispersion is increased, the dispersion stability is further maintained even with time, and the pigment concentration is high. Nevertheless, a pigment dispersion for a color filter that is less likely to deteriorate over time can be obtained.

The "total mass of calcium (Ca) and iron (Fe) contained in the pigment dispersion" is preferably not more than the above upper limit, and the calcium (Ca) is preferably 160 mass ppm or less with respect to the entire pigment dispersion. , 100 mass ppm or less is more preferable, 60 mass ppm or less is particularly preferable, and 30 mass ppm or less is further preferable.
Further, the "total mass of calcium (Ca) and iron (Fe) contained in the pigment dispersion" is not more than the upper limit, and the iron (Fe) is 30 mass ppm or less with respect to the entire pigment dispersion. Is preferable, 20 mass ppm or less is more preferable, 10 mass ppm or less is particularly preferable, and 5 mass ppm or less is further preferable.
When it is not more than the above upper limit, the above-mentioned effect of the present invention is particularly exhibited.

The "total mass of calcium (Ca) and iron (Fe) contained in the pigment dispersion" is equal to or less than the above upper limit, and "calcium (Ca), iron (Fe) and magnesium (Mg) contained in the pigment dispersion". And the total mass of aluminum (Al) and chromium (Cr) ”is preferably 290 mass ppm or less, more preferably 260 mass ppm or less, particularly preferably 190 mass ppm or less, and 100 mass by mass with respect to the entire pigment dispersion. It is more preferably ppm or less, and most preferably 50 mass ppm or less.
When it is not more than the above upper limit, the above-mentioned effect of the present invention is particularly exhibited.

<Principle of action>
The principle of action that exerts the above-mentioned effects of the present invention, such as improvement of dispersion stability, does not limit the scope of the invention, but is considered as follows.
That is, when a large amount of calcium (Ca), iron (Fe), or the specific metal element is present in the vicinity of the organic pigment, it is presumed that the adsorption of the dispersant to the organic pigment is inhibited. Further, it is presumed that the salt-type dispersant or acidic dye derivative that contributes to the improvement of dispersibility forms a salt with the specific metal element, so that the dispersant or the acidic dye derivative cannot contribute to the improvement of dispersibility. ..

In addition, the effect on the decrease in dispersibility is that divalent or higher cations such as cations of specific metal elements are more important than monovalent cations such as sodium ion (Na ⁺ ) and potassium ion (K ⁺ ). It is possible that it is larger. Since the larger the valence of the metal cation has a higher effect on the cohesiveness, "the upper limit of the total mass of Ca and Fe, which are metal elements having a valence of 2 or more, and the same, both It is also considered that the "dispersion stability" was improved as a result of suppressing the "upper limit of the total mass of Mg, Al and Cr, which are metal elements having a valence of divalent or higher".
Further, it is more preferable to suppress the content of Fe, which is a metal element that gives a trivalent cation, more preferably, Al, which is a metal element that also gives a trivalent cation while suppressing the content of Fe. It is also considered that suppressing the content of Cr and Cr greatly affected the improvement of dispersion stability.

Therefore, when the content of the specific metal element is small as specified in the present invention, it is presumed that the above-mentioned obstacles are unlikely to occur, and therefore the dispersibility and the developability described later are improved.

<Method of reducing the metal content in the pigment dispersion>
The pigment dispersion liquid of the present invention contains at least an organic pigment, a dispersant and a solvent, and the metal is brought in from the organic pigment, the dispersant, the solvent and the like which are the raw materials of the pigment dispersion liquid. It can also be mixed from equipment used for stirring, mixing, dispersion and the like. Therefore, it is preferable to prevent the metal from being mixed in from the raw materials and the apparatus.
In particular, it is more preferable to remove the metal from the organic pigment because the amount of the metal brought in from the organic pigment is large.
Further, it is particularly preferable to reduce the amount of the metal from the organic pigment to be blended, and when an acidic dye derivative is used, from those colorants.

The method for removing the metal in the organic pigment is not particularly limited, and the metal may be removed in the process of manufacturing the pigment, or the metal may be removed from the manufactured pigment by a specific removing method.
As a method for removing the metal from the produced pigment, washing with a liquid such as alcohol or water is preferable, but a washing method with water (hereinafter, may be simply abbreviated as "washing with water") is particularly preferable in terms of cost. It is mentioned as a thing.

In addition to the "washing with liquid" such as "washing with water", the members of the manufacturing equipment in the pigment manufacturing process are made of metal such as iron-containing metal such as iron and stainless steel; and chrome-plated members; It is preferable not to use anything.
"Members of manufacturing equipment" include media such as balls in ball mills and beads in bead mills; inner walls of pigment manufacturing containers, dispersion containers, surface treatment containers, drying containers, filtration containers, etc .; members of crushers; members of stirring devices. ; Etc. can be mentioned.

The removal method is particularly preferably washing with water. The water washing may be carried out by suspending the pigment in water and suspending it by a batch method, or by using running water and treating it by a continuous method.

The amount of the specific metal element contained in the organic pigment used in the pigment dispersion liquid of the present invention can be achieved by adjusting or optimizing the following.
That is, as a means for reducing the amount of the specific metal element contained in the organic pigment, the content of the specific metal element contained in the washing water to be used is reduced (demineralized water in which the amount of the metal is sufficiently reduced is used). ), The washing is performed by a continuous method using running water, the number of washings is increased when the washing is a batch method, the amount of washing water is increased with respect to the amount of the pigment in both the continuous method and the batch method, and the temperature of the washing water is adjusted. Examples include increasing the pH, adjusting the pH of the washing water, optimizing the stirring device during washing, and lengthening the washing time.

Among them, a batch method in which the number of washings with water is increased, a continuous method using running water, or a method of raising the temperature of the washing water is particularly preferable.
The temperature of the washing water is more preferably in the range of 20 ° C. to 80 ° C. from the viewpoint of efficiently removing a predetermined metal, particularly preferably in the range of 30 ° C. to 70 ° C., and further preferably in the range of 40 ° C. to 60 ° C. ..
Among them, a continuous method using running water or the like is preferable, and in that case, the amount of running water used is preferably 30 parts by mass to 40,000 parts by mass, and 40 parts by mass to 20,000 parts by mass with respect to 1 part by mass of the organic pigment. More preferably, 50 parts by mass to 10000 parts by mass is particularly preferable, and 60 parts by mass to 5000 parts by mass is further preferable.

Deionized water used for washing is made from raw water treated with strongly acidic or weakly acidic cation exchange resin, strongly basic or weakly basic anion exchange resin, ion exchange membrane, chelate resin, activated charcoal, antibacterial activated charcoal, etc. It is preferably obtained by treating at least one selected, preferably two or more of the above-mentioned treatment agents in combination, or by (reducing pressure) distillation.

The washing with water is not particularly limited, but the organic pigment produced by a known method is suspended in the deionized water, and a vacuum filter, a belt press, a centrifuge, a nutche funnel, etc. are used. Using a continuous method of continuously supplying deionized water for continuous cleaning, a filter press, a homogenizer (high pressure or low pressure homogenizer, ultrasonic homogenizer, etc.), a stirrer such as a sand mill, ball mill, roll mill, magnetic stirrer, etc. Therefore, a batch method of washing while dispersing the organic pigment is preferable.

Above all, in order to reduce the mixing of metals such as calcium (Ca), iron (Fe), magnesium (Mg), aluminum (Al), and chromium (Cr) from the materials and media used, high-pressure or low-pressure homogenizers, ultra A homogenizer such as a sonic homogenizer is more preferable, and an ultrasonic homogenizer is particularly preferable from the viewpoints of reducing the amount of the metal mixed and reducing the cost.

Further, when washing while dispersing the organic pigment using the above-mentioned stirrer, it is also preferable to continuously supply water and treat with running water by a continuous method. That is, it is also preferable to use the above-mentioned stirrer in combination with the continuous method in order to reduce the specific metal element.

In the cleaning step, impurities such as metal salts, free metals, and other inorganic salts in the organic pigment are extracted into the deionized water. After washing, the suspension is filtered to remove impurities extracted in deionized water as a filtrate.
Then, the wet cake of the pigment obtained above is suspended in the deionized water again, and if necessary, the washing treatment is performed several times in the same step as above, and the impurities are removed as a filtrate each time, and finally. It is preferable to dry the wet cake of the obtained pigment to obtain an organic pigment for compounding in the pigment dispersion liquid. From the viewpoint of the balance between the cleaning effect and the cost, the above-mentioned "several times" is preferably 2 to 50 times, more preferably 3 to 40 times, particularly preferably 4 to 30 times, and further preferably 5 to 20 times. The (particularly) preferable mass of the total deionized water used for 1 part by mass of the organic pigment is the same as in the case of the above-mentioned "continuous method using running water".

That is, in a preferred embodiment of washing with water, the organic pigment is washed by a batch method or a continuous method while dispersing the organic pigment in water using a stirrer of "high pressure or low pressure homogenizer, sand mill, ball mill, roll mill, magnetic stirrer, etc." After filtration, it is suspended in fresh water and washed with water, and in the case of the batch method, the above steps are repeated a plurality of times, and the mixture is filtered and dried.

The electrical conductivity of the final filtrate in the washing step is preferably 20 μS / cm or less (particularly preferably 0.05 μS / cm to 5 μS / cm). If the washing method is such that the electric conductivity exceeds the above range, the pigment may be insufficiently washed with water, and the pigment dispersion liquid in which the amount of the above-mentioned metal is reduced to the range of the present invention may not be produced.
That is, a pigment dispersion obtained by using the pigment by repeating the washing treatment to a level comparable to the electric conductivity of the deionized water used for washing the pigment and making the impurities in the pigment almost nonexistent. Exhibits the above-mentioned effect of the present invention.

The final cleaning step for the organic pigment used in the preparation of the pigment dispersion of the present invention can also be confirmed by ICP (Inductively Coupled Plasma) emission spectroscopic analysis of the filtrate. The ICP measurement of the filtrate is carried out in the same manner in the method described in the measurement example <quantification of metal in the pigment dispersion> in the example, in which the "pigment dispersion" in the measurement example is replaced with the "filtrate".

The content of calcium (Ca) and iron (Fe) in the final filtrate of the washing step is preferably not less than the detection limit, and calcium (Ca), iron (Fe), magnesium (Mg), and the like. It is more preferable that both aluminum (Al) and chromium (Cr) are below the detection limit, and calcium (Ca), iron (Fe), magnesium (Mg), aluminum (Al), chromium (Cr), sodium ( It is particularly preferable that both Na) and potassium (K) are below the detection limit.
Here, the detection limit in the measurement method of the present invention (ICP (Inductively Coupled Plasma) emission spectroscopic analysis) is less than 0.01 ppm.

When the "content by ICP measurement" or "electrical conductivity of the filtrate" of each metal atom which is an impurity in the above filtrate exceeds the above upper limit, the content of the predetermined metal in the pigment dispersion liquid is high. Since it may not fall within the above-mentioned range of the present invention, it may not be possible to prepare a pigment dispersion having a high pigment concentration with a low viscosity (optimal viscosity), or dispersion stability may not be achieved.
Therefore, when preparing the pigment, it is preferable to repeat the washing treatment until the content of the metal atom in the filtrate and the electric conductivity of the filtrate are within the above numerical ranges.

<Aspects of pigment dispersion liquid>
The average dispersed particle size of the pigment in the pigment dispersion liquid of the present invention is not particularly limited, but is preferably 8 nm to 150 nm, more preferably 10 nm to 100 nm, and particularly preferably 12 nm to 70 nm.
Here, the average dispersed particle size of the pigment in the pigment dispersion liquid (hereinafter, may be simply abbreviated as "average dispersed particle size") is at least the dispersion of the pigment particles dispersed in the dispersion medium containing a solvent. It is a particle size and is measured by a laser light scattering particle size distribution meter. For the measurement of the particle size by the laser light scattering particle size distribution meter, the pigment dispersion is appropriately diluted with the solvent used in the pigment dispersion to a concentration that can be measured by the laser light scattering particle size distribution meter (for example, 1000 times, etc.). ), A laser light scattering particle size distribution meter (for example, Nanotrack particle size distribution measuring device UPA-EX150 manufactured by Nikkiso Co., Ltd.) is used to measure at 23 ° C. by a dynamic light scattering method. The average dispersed particle size here is the volume average particle size.

If the average dispersed particle size is too small, the light resistance may decrease, while if the average dispersed particle size is too large, the display using the color filter obtained by using the pigment dispersion has a low contrast. In some cases, the light transmittance is low, or the display does not have high brightness.

After dispersion, it is preferable to filter with a filter of usually 0.05 μm to 10 μm, preferably 0.1 μm to 5 μm or the like to obtain the pigment dispersion liquid of the present invention.

<Coloring composition for color filters>
The pigment dispersion of the present invention can be suitably used for a color filter material, a coloring composition for a color filter, a photosensitive coloring resin composition for a color filter, a liquid crystal display material, an organic EL display material, and the like. In particular, it is useful as a coloring composition for a color filter.
Another aspect of the present invention is a coloring composition containing the above-mentioned pigment dispersion for a color filter of the present invention, a polymerization initiator and an alkali-soluble resin, and calcium (Ca) and iron contained in the coloring composition. The coloring composition for a color filter is characterized in that the total mass of (Fe) is 120% by mass or less with respect to the entire coloring composition.
The alkali-soluble resin has a polymerizable functional group, and only the polymerizable functional group of the alkali-soluble resin may be polymerized, but the coloring composition for a color filter further contains a polymerizable polyfunctional compound. It is also preferable.

The coloring composition for a color filter using the pigment dispersion of the present invention exhibits the above-mentioned effects of the present invention.

<< Alkali-soluble resin >>
The alkali-soluble resin is not particularly limited and can be used as long as it can be suitably developed with an alkaline developer.
The alkali-soluble resin is preferably a copolymer containing a monomer having an acid group as a copolymerization component. Further, the polymer may have an acid group introduced later.

Here, as the monomer having an acid group, a monomer having a carboxy group such as (meth) acrylic acid and itaconic acid (methylenesuccinic acid); a monomer having a phenolic hydroxyl group such as 4-hydroxyphenylmaleimide; Monomers having a carboxylic acid anhydride group such as itaconic anhydride; and the like.

Further, the alkali-soluble resin in the present invention has a radically polymerizable double bond introduced therein, but the sensitivity is improved. As a result, the colored composition is image-exposed and photocured, and the unexposed portion is developed. It is preferable from the viewpoint that a good coating film can be formed.
To introduce a radically polymerizable double bond, for example, after (co) polymerization of a monomer capable of introducing a radically polymerizable double bond after polymerization, a radically polymerizable double bond as described later is introduced into the side chain. do.
Examples of the "monomer capable of introducing a radically polymerizable double bond after polymerization" include a monomer having a carboxy group such as (meth) acrylic acid and itaconic acid; and a carboxylic acid anhydride such as maleic anhydride and itaconic anhydride. Monomers having a group; and the like.

Compounds used to introduce radically polymerizable double bonds include "epoxide groups" such as glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, o- or m- or p-vinylbenzyl glycidyl ether. And radically polymerizable double bonds ”.
A radically polymerizable double bond is introduced by reacting the acid group of the "monomer capable of introducing a radically polymerizable double bond after polymerization" with the epoxy group of the compound having "epoxy group and radically polymerizable double bond". The resulting alkali-soluble resin is obtained.

In addition to the above, a monomer copolymerizable with these can be used for the alkali-soluble resin, and an ethylenically unsaturated double bond is used as the monomer (hereinafter abbreviated as “other monomer”). Examples thereof include styrene-based monomers such as styrene and α-methylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate (meth) n-propyl acrylate, (meth). (Meta) such as isopropyl acrylate, butyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, benzyl (meth) acrylate, hydroxyethyl (meth) acrylate, etc. Acrylate-based monomers; (meth) acrylamide-based monomers such as (meth) acrylamide, N-methylolacrylamide, N, N-dimethylacrylamide, N, N-dimethylaminoethylacrylamide, etc .; vinyl acetate; acrylonitrile; allylalkyl ether, etc. Allyl group-containing compounds; maleimide-based monomers such as benzylmaleimide and N-phenylmaleimide; and the like are copolymerized.

The above-mentioned "monomer having an acid group", "monomer capable of introducing a radically polymerizable double bond after polymerization", "compound used for introducing a radically polymerizable double bond" and "other monomer" are used. In some cases, one or more of each is used and subjected to (co) polymerization or reaction.

The acid value of the alkali-soluble resin in the present invention is not particularly limited, but is preferably 30 to 200 mgKOH / g, more preferably 40 to 150 mgKOH / g, and particularly preferably 50 to 120 mgKOH / g.
When the upper limit of the acid value is not more than the above value, sufficient adhesion to the substrate can be obtained, and when the lower limit is not more than the above value, sufficient alkali developability can be obtained.

The molecular weight of the alkali-soluble resin in the present invention is not particularly limited, but is usually 3000 to 25000, preferably 4000 to 20000, and particularly preferably 5000 to 15000 as the polystyrene-equivalent weight average molecular weight (Mw).
When the upper limit of the weight average molecular weight (Mw) is not more than the above value, the compatibility with other constituents is improved, the developability is improved, and the viscosity is not too high. On the other hand, when the lower limit is equal to or higher than the above value, the adhesion to the substrate is improved.

<< Polymerizable polyfunctional compound >>
The polymerizable polyfunctional compound is not particularly limited, and a known polymerizable polyfunctional compound is used.
The "polymerizable polyfunctional compound" is not particularly limited as long as it has two or more polymerizable functional groups in one molecule, and is, for example, polyester (meth) acrylate, polyether (meth) acrylate, or urethane. Polyfunctional (meth) acrylates such as (meth) acrylates and epoxy (meth) acrylates; polyfunctional allyl compounds such as diallylphthalate and triallyl isocyanurate; and the like can be mentioned.

Among these, specific examples of the polyether (meth) acrylate include the following.
Examples of the bifunctional (meth) acrylate include linear alkanediol di (meth) acrylates such as 1,4-butanediol di (meth) acrylate and 1,6-hexanediol di (meth) acrylate; diethylene glycol di (meth) acrylate. ) Acrylate, polyethylene glycol # 200 di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol # 400 di (meth) acrylate; pentaerythritol di (meth) acrylate, etc. Partial (meth) acrylic acid ester of alcohol with trivalent or higher; bisphenol di (meth) acrylate such as bisphenol A di (meth) acrylate, bisphenol F di (meth) acrylate; neopentyl glycol di (meth) acrylate; etc. Can be mentioned.

Examples of the trifunctional (meth) acrylate include glycerin tri (meth) acrylate, glycerin PO-modified tri (meth) acrylate, trimethylol propane tri (meth) acrylate, trimethylol propane EO-modified tri (meth) acrylate, and trimethylol propane. PO-modified tri (meth) acrylate, isocyanuric acid EO-modified tri (meth) acrylate, isocyanuric acid EO-modified ε-caprolactone-modified tri (meth) acrylate, 1,3,5-triacrylloylhexahydro-s-triazine, pentaerythritol tri Examples thereof include (meth) acrylate and dipentaerythritol tri (meth) acrylate tripropionate.

Examples of the tetrafunctional or higher functional (meth) acrylate include pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, succinic acid-modified dipentaerythritol penta (meth) acrylate, and pentaerythritol tri (meth) acrylate. Examples thereof include succinic acid modified products, dipentaerythritol penta (meth) acrylate monopropionate, dipentaerythritol hexa (meth) acrylate, tetramethylol ethanetetra (meth) acrylate, and oligoester tetra (meth) acrylate.

One of these polyfunctional monomers may be used alone, or two or more thereof may be used in combination. For example, a polyfunctional monomer having a carboxy group and a polyfunctional monomer having no carboxy group may be used in combination. Succinic acid modification of pentaerythritol tri (meth) acrylate having a carboxy group and succinic acid modification of dipentaerythritol penta (meth) acrylate having a carboxy group from the viewpoint of improving heat resistance and adhesion. Things and the like are preferable.

<< Polymerization Initiator >>
Examples of the polymerization initiator include thermal polymerization initiators and photopolymerization initiators.
The photopolymerization initiator is not particularly limited, and known ones conventionally used for radical polymerization can be used. In particular, it is preferable to use one that is generally used for manufacturing a color filter.

Specifically, such a photopolymerization initiator is a compound that generates a free radical by the energy of ultraviolet rays, and is a benzoin derivative; a benzophenone derivative; a xanthone derivative such as xanthone, diethylthioxanthone, or isopropylthioxanthone; or a thioxanthone derivative; Irgacure OXE-01, Irgacure OXE-02 (above, manufactured by BASF Japan); oxime ester compounds such as ADEKA OPT-N-1919 (manufactured by Asahi Denka); chlorosulfonyl, chloromethyl polynuclear aromatic compound, chloromethyl heterocyclic formula. Examples thereof include compounds, halogen-containing compounds such as chloromethylbenzophenones; triazines; fluorenones; haloalkanes; redox couples of photoreducing dyes and reducing agents; organic sulfur compounds; peroxides; and the like.

Specific examples of the photopolymerization initiator include aromatic ketone compounds such as Michler ketone, 4,4'-bisdiethylaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-ethylanthraquinone, and phenylanthrene; benzoin. Benzoin ether compounds such as methyl ether, benzoin ethyl ether, benzoin phenyl ether; benzoin compounds such as methyl benzoin and ethyl benzoin; 2- (o-chlorophenyl) -4,5-phenylimidazole dimer, 2- (o-chlorophenyl) ) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5- Biimidazole compounds such as diphenylimidazole dimer, 2,4,5-triarylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (m-methylphenyl) imidazole dimer; 2- Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, 2-trichloromethyl-5-styryl-1,3,4-oxadiazole, 2-trichloromethyl-5- (p-cyanostyryl) )-1,3,4-Oxadiazole, 2-trichloromethyl-5- (p-methoxystyryl) -1,3,4-oxadiazole and other halomethylthiazole compounds; 2,4-bis (trichloromethyl) ) -6-p-methoxystyryl-s-triazine, 2,4-bis (trichloromethyl) -6- (1-p-dimethylaminophenyl-1,3-butadienyl) -s-triazine, 2-trichloromethyl- 4-Amino-6-p-methoxystyryl-s-triazine, 2- (naphth-1-yl) -4,6-bis-trichloromethyl-s-triazine, 2- (4-ethoxy-naphth-1-yl) ) -4,6-bis-Trichloromethyl-s-triazine, 2- (4-butoxy-naphtho-1-yl) -4,6-bis-trichloromethyl-s-triazine and other halomethyl-s-triazine compounds. 2,2-Dimethoxy-1,2-diphenylethan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanol, 1,2-benzyl-2-dimethylamino- 1- (4-morpholinophenyl) -butanone-1,1-hydroxy-cyclohexyl-phenylketone, methyl benzoyl benzoate, 4-benzo Il-4'-methyldiphenylsulfide, benzylmethylketal, dimethylaminobenzoate, p-dimethylaminobenzoate isoamyl, 2-n-butoxyethyl-4-dimethylaminobenzoate, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl] -1- (o-acetyloxime), 4-benzoyl- Methyldiphenyl sulfide, 1-hydroxy-cyclohexyl-phenylketone, 2-benzyl-2- (dimethylamino) -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2- (dimethylamino)- 2-[(4-Methylphenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, α-dimethoxy-α-phenylacetophenone, phenylbis (2,4,6-trimethylbenzoyl) Phenyloxide, 2-methyl-1- [4- (methylthio) phenyl] -2- (4-morpholinyl) -1-propanol, 1,2-octadion and the like can be mentioned.

Further, a photopolymerization initiator having a tertiary amine structure can be preferably used. Since the photopolymerization initiator having a tertiary amine structure has a tertiary amine structure which is an oxygen quencher in the molecule, radicals generated from the photopolymerization initiator are less likely to be deactivated by oxygen, and the sensitivity can be improved. It has the advantage of being able to do it.
Examples of commercially available products of the photopolymerization initiator having the tertiary amine structure include Irgacure 907, Irgacure 369 (all manufactured by BASF Japan, Inc.), and High Cure ABP (manufactured by Kawaguchi Pharmaceutical Co., Ltd.).

The photopolymerization initiator used in the present invention is not limited to one type, and two or more types may be used in combination.

<< Content ratio >>
The content ratio of the alkali-soluble resin and the polymerizable polyfunctional compound in the coloring composition of the present invention is not particularly limited, but is polymerized with respect to 100 parts by mass of the alkali-soluble resin from the viewpoint of sensitivity, resolution and developability. The sex polyfunctional compound is preferably 0 to 500 parts by mass, more preferably 10 to 300 parts by mass, and particularly preferably 20 to 200 parts by mass.
The alkali-soluble resin is preferably 5 to 80% by mass, more preferably 10 to 40% by mass, based on the total solid content of the coloring composition. Further, the polymerizable polyfunctional compound is preferably 5 to 60% by mass, more preferably 10 to 40% by mass, based on the total amount of the solid content.

The content ratio of the polymerization initiator is usually 0.2 to 30 parts by weight, preferably 0.5 to 20 parts by weight, particularly, with respect to 100 parts by weight of the polymerizable polyfunctional compound from the viewpoint of sensitivity, resolution and developability. It is preferably 1 to 10 parts by weight.
The polymerization initiator is preferably 3 to 40% by mass, more preferably 7 to 35% by mass, and particularly preferably 10 to 30% by mass with respect to the total solid content of the coloring composition.

The organic pigment is preferably 3 to 65% by mass, more preferably 6 to 55% by mass, and particularly preferably 10 to 45% by mass with respect to the total solid content of the coloring composition.
Within this range, the above-mentioned effects of the present invention are likely to be exhibited, and in particular, the coloring power, sensitivity, resolution and developability are good. In particular, when the pigment dispersion liquid of the present invention is used, the concentration of the organic pigment can be increased up to the above upper limit, and for that reason, an excellent color filter as described above can be manufactured.

<< Other ingredients >>
Further, if necessary, the coloring composition may include, for example, a surfactant for improving wettability, a leveling agent, a silane coupling agent for improving adhesion, an antifoaming agent, an antioxidant, an antioxidant, and the like. It can contain an anti-aggregation agent, an ultraviolet absorber and the like.

<< Metal content in coloring composition >>
The coloring composition for a color filter of the present invention is a coloring composition containing the pigment dispersion liquid, the polymerization initiator and the alkali-soluble resin of the present invention, and the calcium (Ca) and iron contained in the coloring composition. The total mass of (Fe) is 120 mass ppm or less with respect to the entire coloring composition.

The total mass of calcium (Ca) and iron (Fe) contained in the coloring composition may be as small as possible without considering the cost, but it is preferably 90% by mass or less with respect to the entire coloring composition. 50 mass ppm or less is more preferable, 20 mass ppm or less is particularly preferable, 10 mass ppm or less is further preferable, and 3 mass ppm or less is most preferable.
When it is not more than the above upper limit, the developability is good while maintaining the dispersion stability, so that the pigment concentration in the coloring composition and the pigment concentration in the solid content of the coloring composition can be increased, and as a result. It is possible to obtain a color filter that realizes a high color density even with a low film thickness.

Further, by preparing a coloring composition for a color filter using the pigment dispersion of the present invention, an excellent coloring composition within the above-mentioned metal content range can be prepared, and good dispersion performance and dispersion stability performance can be obtained. At the same time, it is possible to provide a coloring composition for a color filter that is compatible with good development characteristics at the time of manufacturing a color filter.

The lower limit of the "total mass of calcium (Ca) and iron (Fe) contained in the coloring composition" is not particularly limited, but is preferably 0.5 mass ppm or more, and particularly preferably 1 mass ppm or more. When it is at least the above lower limit, the developability is sufficiently good, so that the cost required for removing the metal element is not excessive.

Further, it is preferable that the total mass of magnesium (Mg), aluminum (Al) and chromium (Cr) contained in the coloring composition is 135 mass ppm or less with respect to the entire coloring composition. That is, the total mass of calcium (Ca) and iron (Fe) contained in the coloring composition is 120 mass ppm or less with respect to the entire coloring composition, and magnesium (Mg) and aluminum (Al) are used. The total mass of chromium (Cr) is preferably 135 mass ppm or less with respect to the entire coloring composition.
By preparing a coloring composition for a color filter using the pigment dispersion of the present invention, an excellent coloring composition within the above-mentioned metal content range can be prepared.

The total mass of magnesium (Mg), aluminum (Al) and chromium (Cr) contained in the coloring composition is more preferably 60% by mass or less, particularly preferably 30% by mass or less, still more preferably. , 20 mass ppm or less.
When it is not more than the above upper limit, the above-mentioned effect of the present invention is particularly exhibited.

Further, the "total mass of calcium (Ca) and iron (Fe) contained in the coloring composition" is not more than the above upper limit, and "calcium (Ca), iron (Fe) and magnesium (contained in the coloring composition)". The total mass of Mg), aluminum (Al) and chromium (Cr) is preferably 200 mass ppm or less, more preferably 150 mass ppm or less, and particularly preferably 100 mass ppm or less, based on the entire coloring composition. 50 mass ppm or less is more preferable, and 15 mass ppm or less is most preferable.
When it is not more than the above upper limit, the above-mentioned effect of the present invention is particularly exhibited.

<< Principle of action >>
The present invention is not limited to the range to which the following principle of action applies, but the total mass of calcium (Ca) and iron (Fe) contained in the coloring composition (or the total mass of specific metal elements) is large. If it exceeds the limit, the principle of action in which the dispersion stability deteriorates and the developability deteriorates is presumed as follows.

That is, for example, the nitrogen moiety contained in the a monomer (preferably the structural unit represented by the general formula (1)) in the dispersant is adsorbed on the organic pigment to improve the dispersibility of the organic pigment and the dispersion thereof. It is considered that the organic pigment firmly surrounded by the agent is easily washed away while being adsorbed by the dispersant during development, and the generation of the residue derived from the organic pigment is suppressed on the substrate.
However, if the total mass of calcium (Ca) and iron (Fe) or the total content of the specific metal element is too large in the vicinity of the organic pigment (calcium (Ca), iron (Fe) or the specific metal element is too large). ), The adsorption of the dispersant to the organic pigment is hindered, and the salt-type dispersant or acidic dye derivative that contributes to the improvement of dispersibility cannot contribute to the improvement of dispersibility by interacting with the specific metal element. It is thought that it will happen.

Further, if the content is too large, as described above, the organic pigment is not suitably surrounded by the dispersant. Therefore, at the time of development, the developing solution is in the form of "organic pigment preferably surrounded by the dispersant". It is considered that it became difficult to be washed away at the same time, and a residue derived from an organic pigment was likely to be generated on the substrate (development failure was likely to occur).

The coloring composition exhibits developability because it contains an alkali-soluble resin, but the above-mentioned "salt-type dispersant that does not suitably surround the organic pigment" reduces the developability. Is also possible. Further, the influence of cations of a specific metal element having a valence of 2 or more on the alkali-soluble resin is also considered.
The effect on the deterioration of developability is more than divalent cations (divalent) such as cations of specific metal elements, rather than monovalent cations such as sodium ion (Na ⁺ ) and potassium ion (K ⁺ ). It is considered that the total amount of the above cations only and the content including trivalent cations) may be larger.

Therefore, it is considered that the coloring composition obtained by using the pigment dispersion having good dispersibility stability has good developability.

<< Preparation of coloring composition for color filter >>
In the preparation of the coloring composition of the present invention, at least an alkali-soluble resin and a polymerization initiator are blended in the pigment dispersion liquid, and if necessary, a polymerizable polyfunctional compound and "other components" are blended. Further, if necessary, it can be carried out by a method of further blending and mixing a solvent.
Since the coloring composition of the present invention is used by producing a pigment dispersion liquid in advance, aggregation of the pigment can be effectively prevented and the pigment can be uniformly dispersed.

Further, since the pigment dispersion liquid of the present invention can be set to a high pigment concentration while maintaining a suitable viscosity range and suitable dispersion stability, the coloring of the present invention obtained by using the pigment dispersion liquid of the present invention can be obtained. The composition can also achieve a high pigment concentration while maintaining a suitable viscosity range and a suitable dispersion stability.

<Color filter>
The color filter usually has a transparent substrate, a light-shielding portion, and a colored layer. The color filter obtained by using the pigment dispersion liquid of the present invention or obtained by using the above-mentioned coloring composition can realize high organic pigment concentration, high color rendering property, high contrast and the like, and also. Excellent developability during color filter manufacturing.

<< Colored layer >>
The colored layer may be formed by curing the above-mentioned coloring composition of the present invention, and is not particularly limited, but is usually formed in the opening of the light-shielding portion on the transparent substrate described later, and the coloring composition is described. It is composed of three or more coloring patterns depending on the type of pigment contained in the object.
The arrangement of the colored layers is not particularly limited, and may be, for example, a general arrangement such as a stripe type, a mosaic type, a triangle type, or a 4-pixel arrangement type. Further, the width, area and the like of the colored layer can be arbitrarily set.

The thickness of the colored layer is controlled by adjusting the coating method, coating conditions, solid content concentration of the coloring composition, viscosity, etc., but is usually in the range of 1 to 5 μm.
When the pigment dispersion liquid and the coloring composition of the present invention are used, the pigment concentration in the solid content is high, so that the thickness can be reduced (for example, up to 80 to 50%) with respect to the conventional thickness depending on the composition. .. As a result, the effects of high color rendering, no color mixing, high resolubility, less foreign matter generation, and high productivity are exhibited.

The colored layer can be formed, for example, by the following method.
First, the above-mentioned coloring composition of the present invention is applied onto a transparent substrate described later by using a coating means such as a spray coating method, a dip coating method, a bar coating method, a roll coating method, a spin coating method, and a die coating method. , Form a wet coating.
Next, the wet coating film is dried using a hot plate, an oven, or the like, and then exposed to the wet coating film through a mask having a predetermined pattern to cause a photopolymerization reaction of the alkali-soluble resin and the polymerizable polyfunctional compound.
Examples of the light source used for the exposure include ultraviolet rays such as a low-pressure mercury lamp, a high-pressure mercury lamp, and a metal halide lamp, and an electron beam.
In addition, heat treatment may be performed in order to accelerate the polymerization reaction after exposure.

Next, a coating film is formed in a desired pattern by developing with a developing solution to dissolve and remove the unexposed portion. As the developing solution, a solution in which an alkali is usually dissolved in water or a water-soluble solvent is used. The pigment dispersion liquid and the coloring composition of the present invention are extremely excellent in developability.
After the development treatment, usually, the developer is washed and the cured coating film of the resin composition is dried to form a colored layer. After the development treatment, a heat treatment may be performed in order to sufficiently cure the coating film.

<< Shading part >>
The light-shielding portion of the color filter is formed in a pattern on a transparent substrate described later.
The pattern shape of the light-shielding portion is not particularly limited, and examples thereof include a stripe shape and a matrix shape.
Examples of the light-shielding portion include a black pigment dispersed or dissolved in a binder resin; a metal thin film such as chromium and chromium oxide. This metal thin film may be a CrOx film (x is an arbitrary number) and a Cr film in which two layers are laminated.

When the light-shielding portion is obtained by dispersing or dissolving a black colorant in a binder resin, the method for forming the light-shielding portion includes, for example, a photolithography method using a resin composition for the light-shielding portion, a printing method, or an inkjet. The law etc. can be mentioned.

Further, in the above case, when the photolithography method is used as the method for forming the light-shielding portion, the binder resin may be, for example, reactive with an acrylate-based resin, a methacrylate-based resin, a polyvinyl chloride-based resin, a cyclized rubber-based resin, or the like. A photosensitive resin having a vinyl group is used.
In this case, the resin composition for a light-shielding portion containing a black pigment such as carbon black or titanium black as a pigment and a photosensitive resin includes a photopolymerization initiator, a sensitizer, a coatability improver, a development improver, and a cross-linking agent. , Polymerization inhibitor, plasticizer, flame retardant and the like may be added.

On the other hand, when the light-shielding portion is a metal thin film, as a method for forming the light-shielding portion, for example, a resist pattern obtained by forming a metal thin film vacuum-deposited by a vapor deposition method, a sputtering method, etc. on the metal thin film by a photolithography method is masked. Examples thereof include a method of metal etching.

The film thickness of the light-shielding portion is set to about 0.05 to 0.4 μm in the case of a metal thin film, and 0.5 to 0.5 to 0.5 in the case of a black colorant dispersed or dissolved in a binder resin. It is set at about 3 μm.

<< Transparent substrate >>
The transparent substrate in the color filter may be a substrate that is transparent to visible light, and is not particularly limited, and a transparent substrate used in a general color filter can be used. Specific examples thereof include inflexible transparent rigid materials such as quartz glass, non-alkali glass, and synthetic quartz plates, and flexible transparent flexible materials such as transparent resin films and optical resin plates. Be done.
The thickness of the transparent substrate is not particularly limited, but a transparent substrate of, for example, about 100 μm to 1 mm can be used depending on the intended use.
In addition to the transparent substrate, the light-shielding portion, and the colored layer, the color filter of the present invention may have, for example, an overcoat layer, a transparent electrode layer, an alignment film, a columnar spacer, or the like. ..

<Display device>
Another aspect of the present invention is a display device comprising the above-mentioned color filter. The display device is not particularly limited, and examples thereof include a liquid crystal display and an organic EL display.
The color filter obtained by using the coloring composition containing the pigment dispersion liquid of the present invention is suitably used for display display devices such as liquid crystal displays and organic EL displays.
The application of the color filter to a liquid crystal display or an organic EL display is usually performed by a known method.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded.

Preparation Example 1
<Preparation of Dispersant A (Dispersant Solution A)>
<< Synthesis of Block Copolymer A >>
The 500 mL 4-port separable flask was depressurized and dried, and then the inside was replaced with argon (Ar).
While flowing with argon, add 100 g of dehydrated tetrahydrofuran (THF), 2.0 g of methyltrimethylsilyldimethylketene acetal, 0.15 mL of a 1 M acetonitrile solution of tetrabutylammonium-3-chlorobenzoate (TBACB), and 0.2 g of mesitylene and stir. And mixed.
Using a dropping funnel, 36.7 g of methyl methacrylate was added dropwise thereto over 45 minutes. Since heat was generated as the reaction proceeded, the temperature was kept below 40 ° C. by cooling with ice. After 1 hour, 13.3 g of dimethylaminoethyl methacrylate (DMAEMA) as the "a monomer" was added dropwise over 15 minutes. After reacting for 1 hour, 5 g of methanol was added to stop the reaction.

The solvent was removed under reduced pressure to obtain block copolymer A.
The mass average molecular weight determined by GPC measurement (NMP, LiBr10 mM) was 6000. The amine value was 95 mgKOH / g.
The obtained dispersant A was dissolved in propylene glycol monoethyl ether acetate (PGMEA) to prepare a block copolymer solution of 60% by mass.

<< Step of salting block copolymer (step of preparing basic block-type dispersant) >>
Next, in a 100 mL round bottom flask, 5.0 parts by mass of the block copolymer solution obtained above was mixed with 23.76 parts by mass of PGMEA, and phenylphosphonic acid (Tokyo Kasei (Tokyo Kasei (Tokyo Kasei)), which is a salt-forming component, was mixed. (Manufactured by Co., Ltd.) was added in an amount of 0.94 parts by mass (0.5 mol equivalent to the DMAEMA unit of the block polymer), and the mixture was stirred at a reaction temperature of 40 ° C. for 2 hours to obtain "Dispersant A". , Appropriately diluted with PGMEA to prepare a "dispersant solution A" having a solid content of 20% by mass.

Preparation Example 2
<Preparation of Dispersant B (Dispersant Solution B)>
<< Synthesis of Block Copolymer B >>
To a 500 mL round bottom 4-port separable flask equipped with a condenser, an addition funnel, an inlet for nitrogen, a mechanical stirrer, and a digital thermometer, 250 parts by mass of dehydrated tetrahydrofuran (THF) and 0.6 parts by mass of lithium chloride were added. Sufficient nitrogen substitution was performed.
After cooling the reaction flask to -60 ° C, 4.9 parts by mass of butyl lithium (15% by mass hexane solution), 1.1 parts by mass of diisopropylamine, and 1.0 part by mass of methyl isobutyrate were injected using a syringe. ..

As the "b monomer", 2.2 parts by mass of 1-ethoxyethyl methacrylate (EEMA), 18.7 parts by mass of 2-hydroxyethyl methacrylate (HEMA), and 12.8 parts by mass of 2-ethylhexyl methacrylate (EHMA). , 13.7 parts by mass of n-butyl methacrylate (BMA), 9.5 parts by mass of benzyl methacrylate (BzMA), and 17.5 parts by mass of methyl methacrylate (MMA) over 60 minutes using an addition funnel. Dropped.
After 30 minutes, 26.7 parts by mass of dimethylaminoethyl methacrylate (DMAEMA), which is the "a monomer", was added dropwise over 20 minutes.

After reacting for 30 minutes, 1.5 parts by mass of methanol was added to stop the reaction. The obtained precursor block copolymer THF solution was reprecipitated in hexane, purified by filtration and vacuum drying, and diluted with PGMEA to obtain a solid content of 30% by mass.
32.5 parts by mass of water was added, the temperature was raised to 100 ° C., and the mixture was reacted for 7 hours to deprotect the constituent units derived from EEMA to obtain constituent units derived from methacrylic acid (MAA).
The obtained block copolymer PGMEA solution is reprecipitated in hexane, purified by filtration and vacuum drying, and "A block containing the structural unit represented by the general formula (1)" and "carboxy group-containing monomer". A block copolymer B containing a "B block having a solvent-like property and containing a constituent unit of origin" was obtained.

The acid value of block copolymer B was 8 mgKOH / g, and the Tg was 38 ° C.
When the obtained block copolymer B was confirmed by GPC (gel permeation chromatography), the weight average molecular weight Mw was 7730. The amine value was 95 mgKOH / g.

<< Step of salting block copolymer (step of preparing basic block-type dispersant) >>
Next, salt formation was carried out in the same manner as in Preparation Example 1 to prepare "dispersant B", which was further diluted with PGMEA to prepare "dispersant solution B" having a solid content of 20% by mass.
Similar to Preparation Example 1, 0.5 mol equivalent of phenylphosphonic acid (manufactured by Tokyo Kasei Co., Ltd.), which is a salt-forming component, was added to "DMAEMA unit which is a monomer" of block copolymer B.

Preparation Example 3
<Purification of organic pigments>
Put 2.0 parts by mass of the organic pigment (R-1) shown in Table 1 and 100 parts by mass of ion-exchanged water in a beaker, and stir for 10 minutes with an ultrasonic homogenizer by a batch method while keeping the temperature at 30 ° C. Filtration was performed using filter paper.
Manufacturing and sales company: ADVANTEC
Product name: FIKTER PAPER QUANTITAIVE ASHLESS
Standard: 5C, 150mm (100CIRCLES)

The method of performing the above-mentioned washing (washing with water) twice is referred to as "purification method 1" (reference example 1), the method of performing 20 times is referred to as "purification method 2" (reference example 2), and the method of performing 30 times is referred to as "refining method 2". Purification method 3 ”(Reference Example 3, Example 9).

Further, using 2.0 parts by mass of the organic pigment (R-1) shown in Table 1, using a Nutche funnel, 30,000 parts by mass of total ion-exchanged water was continuously flowed for 15 minutes and suctioned by a continuous method. It was washed (washed with water) by filtration. Then, filtration was performed using the above filter paper.
The temperature of the flowed ion-exchanged water was 30 ° C. This method was referred to as "purification method 4" (Reference Example 4).

Purified organic pigments were prepared using purification methods 1-4.
In Reference Examples 5 to 8 and Comparative Examples 1 to 3, the organic pigments were not purified.
Using the obtained (purified) organic pigments, pigment dispersions were prepared as in the following Examples or Reference Examples 1 to 9 and Comparative Examples 1 to 3.

Preparation Example 4
<Synthesis of resin 1>
A mixture of 40 parts by mass of BzMA, 15 parts by mass of MMA, 25 parts by mass of MAA, and 3 parts by mass of AIBN was placed in a polymerization tank containing 150 parts by mass of PGMEA under a nitrogen stream at 100 ° C. Dropped over time. After completion of the dropping, the mixture was further heated at 100 ° C. for 3 hours to obtain a polymer solution.
The weight average molecular weight of the polymer in this polymer solution was 7000.

Next, 20 parts by mass of GMA, 0.2 parts by mass of triethylamine, and 0.05 part by mass of p-methoxyphenol were added to the obtained polymer solution, and the mixture was heated at 110 ° C. for 10 hours to obtain the main chain. Resin 1 was synthesized by reacting the carboxy group of methacrylic acid with the epoxy group of GMA.
During the reaction, air was bubbled into the reaction solution to prevent the polymerization of GMA. The reaction was followed by measuring the acid value of the solution.

The obtained resin 1 is a resin in which a side chain having an ethylenic double bond is introduced into the main chain of a polymer formed by copolymerization of BzMA, MMA and MAA using GMA, and has a solid content of 40 mass. %, The acid value was 74 mgKOH / g, and the weight average molecular weight was 12000.

<< Abbreviated name >>
BzMA Benzyl Methacrylate MMA Methyl Methacrylate MAA Methacrylic Acid GMA Glycidyl Methacrylate AIBN Azobisisobutyronitrile PGMEA Propylene Glycol Monomethyl Ether Acetate

Preparation Example 5
<Synthesis of acidic dye derivatives>
374.76 parts by mass of fuming sulfuric acid having a sulfur trioxide content of 11% by mass was stirred while cooling to 10 ° C., and 74.96 parts by mass of Pigment Yellow 138 was added. Then, the mixture was stirred at 90 ° C. for 6 hours. The obtained reaction solution was added to 1600 parts by mass of ice water, stirred for 15 minutes, and then the precipitate was filtered.
The obtained wet cake was washed 3 times with 800 parts by mass of demineralized water. The washed wet cake was vacuum dried at 80 ° C. to obtain a yellow pigment sulfonated derivative which is an acidic pigment derivative. The molecular weight was measured by TOF-MS, and it was confirmed that the product was a synthetic object.

Reference example 1
<Preparation of pigment dispersion>
16.7 parts by mass of "solid content 40% by mass PGMEA solution of resin 1 (BzMA / MMA / MAA / GMA = 40/15/25/20 (mass ratio), weight average molecular weight 12000)" obtained in Preparation Example 4. , 8.1 parts by mass of the dispersant solution A and 62.2 parts by mass of PGMEA were stirred and mixed with a dissolver to uniformly dissolve them.

To this solution, 12.7 parts by mass of the (purified) organic pigment obtained in Preparation Example 3 and 0.3 parts by mass of the acidic dye derivative obtained in Preparation Example 5 were added, and the zirconia beads 100 having a particle size of 2.0 mm were added. The mass portion was placed in a mayonnaise bottle and shaken with a paint shaker (manufactured by Asada Iron Works Co., Ltd.) for 1 hour as preliminary crushing.
Next, 200 parts by mass of zirconia beads having a particle size of 2.0 mm were taken out, and 200 parts by mass of zirconia beads having a particle size of 0.1 mm were added. Prepared.

Examples or Reference Examples 2-7, 9
<Preparation of pigment dispersion>
The organic pigment and the dispersant were changed as shown in Table 1, and the (purified) organic pigment obtained in Preparation Example 3 was used in the same manner as in Reference Example 1 in Examples or Reference Examples 2 to 7, 9. Pigment dispersion was prepared. In Reference Examples 5 to 8, the organic pigment itself used is not washed with water because the content of the specific metal element is small.

Reference example 8
<Preparation of pigment dispersion>
The organic pigment is changed to (G-1) as shown in Table 1, and the dispersant A (dispersant solution A) is changed to BYK21116 (basic block type dispersant manufactured by Big Chemie Japan Co., Ltd.) (dispersant in terms of solid content). A green pigment dispersion was prepared in the same manner as in Examples or Reference Examples 1 to 7 except that A and the dispersant B were used in the same mass). In Reference Example 8, the organic pigment (G-1) itself used is not washed with water because the content of the specific metal element is small.

Comparative Examples 1 to 3
Except for changing the organic pigments as shown in Table 1 and using "organic pigments that are not purified organic pigments purified as in Preparation Example 3" (except that the organic pigments were not purified), reference example 1 and Similarly, the pigment dispersions of Comparative Examples 1 to 3 were prepared.

Examples or Reference Examples 11-19
Comparative Examples 11 to 13
<Preparation of coloring composition for color filter>
Examples or Reference Examples 11 to 19 use the pigment dispersions of Examples or Reference Examples 1 to 9, respectively, and Comparative Examples 11 to 13 use the pigment dispersions of Comparative Examples 1 to 3, respectively, and PGMEA, if necessary. The solid content concentration was adjusted with, and each component was mixed with the composition shown below to prepare a coloring composition for a color filter.

-Pigment dispersion prepared in Examples or Reference Examples 1 to 9 and Comparative Examples 1 to 3 (solid content: 21.3% by mass): 52.7 parts by mass, the same as the resin 1 used in Reference Example 1, respectively. Alkali-soluble resin: 3.04 parts by mass, polymerizable polyfunctional compound (manufactured by Toa Synthetic Co., Ltd., Aronix M-403, photocurable polyfunctional monomer): 2. 84 parts by mass, polymerization initiator (BASF, Irgacure 907, photopolymerization initiator): 0.89 parts by mass, surfactant (DIC Co., Ltd., Megafuck F-559): 0.03 parts by mass. -PGMEA: 40.5 parts by mass

Measurement example <Quantification of metal in pigment dispersion>
Using an ICP (Inductively Coupled Plasma) emission spectroscopic analyzer (Varian, Vista-PRO), calcium (Ca), iron (Fe), magnesium (Mg), aluminum (Al) and chromium (Al) in the pigment dispersion The content of Cr) was quantified.
The measurement sample was prepared as follows. That is, about 1 g (0.5 to 1.5 g) of the pigment dispersion is precisely weighed, heated on a burner and in an electric furnace (700 ° C.), incinerated, and then aqua regia is added to make it hot. Heated on a plate to dissolve.
The obtained solution was diluted with ultrapure water to make a total of 50.000 g as a measurement sample.

The detection limit of ICP emission spectroscopic analysis in the present invention is less than 0.01 ppm.
“0 mass ppm” in Tables 1 and 2 indicates that rounded to the nearest “1” is “0”, that is, less than 0.5 mass ppm. Since the measurement sample is diluted about 50 times as described above, "0" in the table thus indicates that it is below the above detection limit of the measuring device.

Evaluation example <Evaluation method of "dispersion stability" of pigment dispersion liquid>
The pigment dispersions prepared in each Example and each Comparative Example were stored at room temperature (25 ° C.), and the viscosities were measured 1 day and 1 month after the preparation. The viscosity was measured at 25.0 ± 1.0 ° C. using a vibration viscometer (VM-200T2 manufactured by Sekonic), and the value 30 seconds after the start of measurement was adopted.

<< Judgment Criteria >>
The viscosity after 1 day of preparation was compared with the viscosity after storage for 1 month, and the determination was made as follows.
AA: Viscosity change within 3% A: Viscosity change exceeds 3% and within 5% B: Viscosity change exceeds 5% and within 7% C: Viscosity change exceeds 7% and within 10% D: Viscosity Change exceeds 10%

The results are shown in Table 1. If the change in viscosity is within 7%, that is, if the "dispersion stability" is "B" or more, the stability is excellent and it is evaluated to be a practical level.

<Evaluation method of "optical characteristics" of coloring composition for color filter>
The coloring composition obtained in each Example and each Comparative Example was placed on a glass substrate (manufactured by NH Technoglass Co., Ltd., “NA35”) using a spin coater to obtain a desired color (red coloring layer) after post-baking. : C light source x = 0.650, green colored layer: y = 0.450, yellow colored layer: y = 0.500). After heat-drying on a hot plate at 80 ° C. for 3 minutes, ultraviolet rays of 60 mJ / cm ² were irradiated using an ultra-high pressure mercury lamp, and then post-baked in a clean oven at 230 ° C. for 25 minutes.

The contrast, chromaticity (x, y), and luminance (Y) of the obtained colored film were measured. The contrast was measured using a "contrast measuring device CT-1B" manufactured by Tsubosaka Electric Co., Ltd., and the chromaticity and brightness were measured using a "microspectroscopy measuring device OSP-SP200" manufactured by Olympus Corporation.
The results are shown in Table 2.

<< Judgment Criteria >>
The contrast is evaluated to be excellent if the red colored layer is 12,000 or more, the green colored layer is 18,000 or more, and the yellow colored layer is 10,000 or more.

<Evaluation method of "developability" of coloring composition for color filter>
The coloring composition for a color filter obtained in each Example and each Comparative Example was applied onto a glass substrate (“NA35” manufactured by NH Techno Glass Co., Ltd.) using a spin coater, and then a hot plate was applied. It was dried at 80 ° C. for 3 minutes.
This colored layer was exposed to ultraviolet rays of 60 mJ / cm ² using an ultra-high pressure mercury lamp via an independent fine line pattern photomask with a line width of 1 μm to 100 μm, thereby forming a thickness of 2.0 μm on a glass substrate. A colored layer was formed.

Next, a 0.05 mass% potassium hydroxide (KOH) aqueous solution was used as a developing solution for spin development, and after contacting with the developing solution, the development process was carried out by washing with pure water to form a pattern and developability. Was evaluated.

In the above development process, the time until the unexposed portion was melted and removed was measured. The end of development was visually observed and the development time was determined according to the following criteria.

<< Judgment Criteria >>
AA: Less than 40 seconds A: 40 seconds or more and less than 60 seconds B: 60 seconds or more and less than 80 seconds C: 80 seconds or more and less than 120 seconds D: 120 seconds or more

The results are shown in Table 2.
If the development time is less than 40 seconds (AA), the "developability" is particularly excellent, and if the development time is 40 seconds or more and less than 60 seconds (A), the "developability" is more excellent and the development time is better. If it is 60 seconds or more and less than 80 seconds (B), the "developability" is excellent, and all of AA, A, and B are good, and it is judged to be a practical level.
On the other hand, if the development time is 80 seconds or more (C, D), the "developability" is inferior, and it is determined that the development time is not at a practical level.

In Table 1, the organic pigments are as follows.
"R-1": Color index R177, manufactured by BASF, Chromophthalred A3B.
"R-2": Color index R177, manufactured by BASF, Chromophthalred A2B.
"R-3": Color index R177, manufactured by BASF, Irgazine Red A2BN.
"R-4": Color index R177, FAST RED A3B manufactured by Yuri Kako Co., Ltd.
"Y-1": Color index Y138, and Paliotor Yellow K0961HD manufactured by BASF.
"G-1" is a color index G58, and is a FASTOGEN Green A110 manufactured by DIC Corporation.

The contents of sodium (Na) and potassium (K) are not shown in Table 1, but were almost the same in all the examples.
Although not shown in Table 1, in Examples or Reference Examples 1 to 9, the initial viscosity of the pigment dispersion was as low as 20 mPa · s or less in spite of the high pigment concentration, which was within the practical range.
The viscosity was measured at 25.0 ± 1.0 ° C. using a vibration viscometer (manufactured by Sekonic, VM-200T2). If the viscosity of the pigment dispersion is 20 mPa · s or less, it is within the practical range.

<Results on pigment dispersion>
As can be seen from Table 1, in any of the examples in which the total mass of calcium (Ca) and iron (Fe) contained in the color filter pigment dispersion is 180 mass ppm or less with respect to the entire color filter pigment dispersion. However, the dispersion stability was judged as "AA", "A" or "B", which was a practical level.
On the other hand, in the comparative example in which the total mass of calcium (Ca) and iron (Fe) is more than 180 mass ppm with respect to the entire pigment dispersion for color filter, the dispersion stability is determined to be "C" or "D". It did not reach the practical level.
It was also found that the above results can be said regardless of the type of pigment. Further, even if the total concentration of calcium (Ca) and iron (Fe) is lowered by washing (Examples or Reference Examples 1 to 4, 9), even if the total concentration is low from the beginning (Reference Examples 5 to 8). , It was found that the dispersion stability was high. It was also found that the above tendency can be said regardless of the type of pigment.

Further, before washing with water, the total concentration of calcium (Ca) and iron (Fe) is more than 180 mass ppm with respect to the entire pigment dispersion for color filter, and the dispersion stability is judged to be "C" in "Comparative Example 1". In Examples or Reference Examples 1 to 4 and 9, the total concentration of calcium (Ca) and iron (Fe) in the pigment dispersion was reduced to 180 mass ppm or less by washing the organic pigment (R-1) with water. In each case, the dispersibility was determined to be "A" or "AA".

When the number of washings (washing with water) was increased, the dispersion stability was improved (Reference Examples 1 to 3), and when the washing (washing with water) was performed by the continuous method, the dispersion stability was excellent (Reference Example 4).
Further, when the reference example 3 and the example 9 in which the organic pigment and the purification method are unified and only the dispersant is changed are compared, the judgment is "AA", but the example 9 using the dispersant B is better. , The dispersion stability was superior to that of Reference Example 3 using the dispersant A.

<Results on coloring compositions for color filters>
Further, as can be seen from Table 2, the example in which the total mass of calcium (Ca) and iron (Fe) contained in the coloring composition for a color filter is 120 mass ppm or less with respect to the entire coloring composition for a color filter. In each case, the developability was judged as "AA", "A" or "B", and it was excellent or at a practical level.
On the other hand, in the comparative example in which the total mass of calcium (Ca) and iron (Fe) is more than 120 mass ppm with respect to the entire coloring composition for the color filter, the developability is judged to be "C" or "D". Yes, it did not reach the practical level. It was also found that the above tendency can be said regardless of the type of pigment.

Further, when the reference example 13 and the example 19 in which the organic pigment and the purification method are unified and only the dispersant is changed are compared, the example 19 using the dispersant B is the reference example 13 using the dispersant A. The developability was better and the judgment was "AA".

Since the pigment dispersion liquid and the coloring composition using the pigment dispersion liquid having a specific metal content of the present invention have high pigment concentration, low viscosity, and high dispersion stability, it is possible to reduce the film thickness of the color filter. Therefore, it is widely used in the manufacture of various displays and the like.

Claims (13)

A pigment dispersion for a color filter containing an organic pigment, a dispersant and a solvent.
The total mass of calcium (Ca) and iron (Fe) contained in the color filter pigment dispersion is 180% by mass or less with respect to the entire color filter pigment dispersion, and further, the color filter pigment dispersion. The total mass of magnesium (Mg), aluminum (Al) and chromium (Cr) contained in the liquid is 140% by mass or less with respect to the entire pigment dispersion for color filter.
The dispersant is a basic block copolymer containing an A block containing a structural unit represented by the following general formula (1) and a B block containing a structural unit derived from a carboxy group-containing monomer. Pigment dispersion for color filters.

[In the general formula (1), R ¹ is a hydrogen atom or a methyl group, A is a divalent linking group, and R ² and R ³ are each independently a hydrocarbon group which may contain a hydrogen atom or a hetero atom. Represented, R ² and R ³ may be bonded to each other to form a ring structure. ] The total mass of calcium (Ca), iron (Fe), magnesium (Mg), aluminum (Al), and chromium (Cr) contained in the color filter pigment dispersion is the total mass of the color filter pigment dispersion. The pigment dispersion for a color filter according to claim 1, which is 100% by mass or less. Claim 1 or claim, wherein the solvent contains one or more solvents selected from the group consisting of alkylene glycol monoalkyl ether acetates, dialkylene glycol monoalkyl ether acetates and trialkylene glycol monoalkyl ether acetates. 2. The pigment dispersion liquid for a color filter according to 2. The pigment dispersion for a color filter according to any one of claims 1 to 3, wherein the acid value of the dispersant is 2 to 50 mgKOH / g. The pigment dispersion for a color filter according to any one of claims 1 to 4, which contains 3 to 40 parts by mass of the organic pigment with respect to 100 parts by mass of the pigment dispersion. The organic pigment comprises an acidic dye derivative having one or more acidic groups selected from the group consisting of a sulfo group, a sulfonamide group, a carboxy group, and a metal salt or an ammonium salt of the functional group. The pigment dispersion for a color filter according to any one of claim 5. The acidic dye derivative is a dye derivative having an acidic group and having one or more pigment skeletons selected from the group consisting of anthraquinone pigments, diketopyrrolopyrrole pigments, azo pigments, quinophthalone pigments, dioxazine pigments and phthalocyanine pigments. The pigment dispersion for a color filter according to claim 6. In the basic block copolymer, the following general formulas (2) to (4) are used so that nitrogen in at least a part of the structural units represented by the general formula (1) becomes a cation. The color according to any one of claims 1 to 7, which is a salt-type block copolymer obtained by binding one or more compounds selected from the group consisting of the represented compounds to form a salt. Pigment dispersion for filters.

[In the general formula (2), Ra has ^a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms; may have a substituent, a vinyl group, a phenyl group or a benzyl group; or-. Represents O-R ^e , where ^Re is a linear, branched or cyclic alkyl group with 1 to 20 carbon atoms; may have a substituent, a vinyl group, a phenyl group or a benzyl group; or a carbon number of carbon atoms. Represents a (meth) acryloyl group via 1 to 4 alkylene groups. ]

[In the general formula (3), R ^b , R ^b'and R ^{b "} are independent of each other and have a hydrogen atom; an acidic group or an ester group thereof; a direct group having 1 to 20 carbon atoms which may have a substituent. A chain, branched or cyclic alkyl group; a vinyl group which may have a substituent, a phenyl group or a benzyl group; or —OR ^{f, where R f may} have a substituent, carbon. A linear, branched or cyclic alkyl group of number 1-20; optionally having a substituent, a vinyl group, a phenyl group or a benzyl group; or a (meth) acryloyl mediated by an alkylene group of 1 to 4 carbon atoms. Represents a group, where X represents a chlorine atom, a bromine atom or an iodine atom.]

[In the general formula (4), R ^c and R ^d may each independently have a hydrogen atom; a hydroxyl group; a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms; and a substituent. , Vinyl group, phenyl group or benzyl group; or —O—R ^e ; ^Re may have a linear, branched or cyclic alkyl group with 1 to 20 carbon atoms; a substituent. It represents a vinyl group, a phenyl group or a benzyl group; or a (meth) acryloyl group via an alkylene group having 1 to 4 carbon atoms. However, at least one of R ^c and R ^d contains a carbon atom. ] Any of claims 1 to 8, wherein the organic pigment is one or more organic pigments selected from the group consisting of anthraquinone pigments, diketopyrrolopyrrole pigments, azo pigments, quinophthalone pigments, dioxazine pigments and phthalocyanine pigments. The pigment dispersion for a color filter according to the above claim. A coloring composition containing the pigment dispersion for a color filter, a polymerization initiator and an alkali-soluble resin according to any one of claims 1 to 9, wherein calcium (Ca) contained in the coloring composition is contained. ) And iron (Fe) have a total mass of 120 mass ppm or less with respect to the entire coloring composition, and further, magnesium (Mg), aluminum (Al), and chromium (Cr) contained in the coloring composition. A coloring composition for a color filter, characterized in that the total mass is 60% by mass or less with respect to the entire coloring composition. The coloring composition for a color filter according to claim 10, which contains 3 to 65% by mass of the organic pigment with respect to the total solid content of the coloring composition. A color filter comprising a colored layer which is a cured product of a colored composition for a color filter containing the pigment dispersion for a color filter according to any one of claims 1 to 9. A display device having the color filter according to claim 12.