CN113462194B - Red pigment dispersion composition for color filter - Google Patents

Abstract

The invention provides a red pigment dispersion composition for a color filter, which can form a coating film with excellent color reproducibility even in a film when using quantum dots as backlight light sources. A red pigment dispersion composition for a color filter, which has a film thickness of 3 μm or less when a coating film is formed under the conditions that the chromaticity (x, y) value in an XYZ color system measured using a C light source in a CIE1931 color system as a light emitting element is in the chromaticity range of x= 0.6700 to 0.6900 and y= 0.3100 to 0.3300; when the transmittance at the wavelength anm is T (a), the [ T (630) -T (600) ]/[ T (600) -T (590) ] of the coating film is 1.9 or more.

Description

Red pigment dispersion composition for color filter

Technical Field

The present invention relates to a red pigment dispersion composition for a color filter.

Background Art

As an indispensable technology for realizing high image quality (high image quality) of image display devices, there is a technology for forming a high-definition (high-resolution) color filter. As color filters, there are: color filters obtained by arranging two or more fine bands (stripes) of different hues in parallel on the surface of a transparent substrate such as glass, and color filters obtained by arranging fine pixels in a predetermined arrangement vertically and horizontally on the surface of a transparent substrate such as glass.

The pixel size is a tiny size of tens to hundreds of micrometers, but it needs to be arranged in a predetermined order for each hue. In addition, the basic performance of the pixel of each hue is required to be high in color purity and visible light transmittance and high in contrast.

Conventionally, for example, a technology for forming a color filter using a coloring composition has been disclosed, characterized in that the coloring composition containing (A) a coloring agent, (B) a binder resin, and (C) a polymerizable compound contains C.I. Pigment Red 264 and an isoindoline pigment as (A) a coloring agent (for example, Patent Document 1).

In recent years, in the field of image display devices, there has been an increasing demand for displaying images with more beautiful and natural rich colors through accurate color expression.

For example, a color filter that can realize chromaticity coordinates of x=0.6700 to 0.6900 and y=0.3100 to 0.3300 in the XYZ color system for red is required.

On the other hand, from the viewpoint of achieving excellent color reproducibility, development of backlight light sources using quantum dot technology is underway.

As such a backlight source, for example, a backlight source having a peak central wavelength in the range of about 615 nm to about 630 nm and showing a narrow emission profile in the range of about 25 nm to about 60 nm in terms of half-width at half maximum (FWHM) is disclosed (eg, Patent Document 2).

Therefore, a color filter used in an image display device including a light source including quantum dots is required to have a property of efficiently transmitting light of a specific wavelength (for example, 615 nm to 630 nm).

Furthermore, in recent years, in order to reduce the thickness of image display devices, color filters formed of thin films have been required.

However, with respect to conventional coloring compositions, when quantum dots are used as a backlight source, it is not possible to obtain a red pigment dispersion composition having the properties of being able to achieve chromaticity coordinates of x=0.6700 to 0.6900 and y=0.3100 to 0.3300 in the XYZ color system, being able to form a coating film that can be made thinner, and being able to efficiently transmit light from a light source containing quantum dots, and there is room for improvement.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2014-178676

Patent Document 2: Japanese Patent Application No. 2013-539598

Summary of the invention

Problem that the invention aims to solve

In view of the above problems, an object of the present invention is to provide a red pigment dispersion composition for color filters which can form a coating film that can achieve excellent color reproducibility even in a thin film when quantum dots are used as a backlight source.

Means used to solve problems

The red pigment dispersion composition for color filter of the present invention has a film thickness of less than 3 μm when forming a coating film under the conditions of a chromaticity (x, y) value in the XYZ color system measured using the C light source in the CIE1931 color system as the light-emitting element and a chromaticity range of x=0.6700~0.6900 and y=0.3100~0.3300; when the transmittance at a wavelength of ann is set to T(a), [T(630)-T(600)]/[T(600)-T(590)] of the coating film is greater than 1.9.

The red pigment dispersion composition for color filter of the present invention preferably contains C.I. Pigment Red 179 and C.I. Pigment Yellow 139 in a mass ratio of C.I. Pigment Red 179/C.I. Pigment Yellow 139 = 95/5 to 40/60.

Furthermore, C.I. Pigment Violet 29 is preferably contained in an amount of 5 to 50% by mass based on the total mass of the C.I. Pigment Red 179 and the C.I. Pigment Yellow 139.

In addition, the red pigment dispersion composition for color filter of the present invention preferably contains a pigment dispersant, a pigment dispersion aid, an alkali-soluble resin, and an organic solvent.

In addition, the pigment dispersant is preferably a polymer pigment dispersant containing a basic group.

In addition, it is preferred that the basic group-containing polymer pigment dispersant is an acrylic block copolymer containing a nitrogen atom.

In addition, it is preferred that the pigment dispersing aid is a pigment dispersing aid containing a sulfonic acid group.

Furthermore, the red pigment dispersion composition for color filter of the present invention is preferably used for a color filter of an image display device including a light source including quantum dots.

Next, the red pigment dispersion composition for color filter of the present invention will be described in detail.

＜Red pigment dispersion composition for color filter＞

The red pigment dispersion composition for color filter of the present invention has a film thickness of less than 3 μm when the chromaticity (x, y) values in the XYZ color system measured using the C light source in the CIE1931 color system as the light-emitting element are within the chromaticity range of x=0.6700 to 0.6900 and y=0.3100 to 0.3300; and when the transmittance at a wavelength of ann is set to T(a), [T(630)-T(600)]/[T(600)-T(590)] of the coating is greater than 1.9.

Here, the chromaticity (x, y) value of the color in the XYZ colorimetric system means a chromaticity value measured using a C light source in the CIE1931XYZ colorimetric system.

The red pigment dispersion composition for color filters of the present invention forms a coating film under the conditions that the chromaticity (x, y) values in the XYZ color system measured using the C light source in the CIE1931 color system as the light-emitting element are in the chromaticity range of x=0.6700 to 0.6900 and y=0.3100 to 0.3300, and the film thickness is 3 μm or less.

By having such a film thickness, a color filter having excellent color rendering properties can be obtained.

The red pigment dispersion composition for color filter of the present invention has a chromaticity (x, y) value in the XYZ colorimetric system measured using the C light source in the CIE1931 colorimetric system as a light-emitting element in the range of x=0.6700 to 0.6900 and y=0.3100 to 0.3300, and when a coating film is formed under the conditions of this chromaticity range, when the transmittance at a wavelength of ann is set to T(a), [T(630)-T(600)]/[T(600)-T(590)] is greater than 1.9.

By having such a transmittance, a color filter having excellent color rendering properties can be obtained.

The above-mentioned [T(630)-T(600)]/[T(600)-T(590)] is preferably 2.0 or more.

The transmittance can be measured by using a spectrophotometer (manufactured by Shimadzu Corporation, UV-2500PC, light source C, 2° field of view).

(pigment)

The red pigment dispersion composition for color filter of the present invention preferably contains C.I. Pigment Red 179 and C.I. Pigment Yellow 139 in a mass ratio of C.I. Pigment Red 179/C.I. Pigment Yellow 139 = 95/5 to 40/60.

By containing C.I. Pigment Red 179 and C.I. Pigment Yellow 139 at a specific mass ratio, the film thickness at the above-mentioned specific chromaticity coordinates can be appropriately controlled to 3 μm or less.

Preferably, the red pigment dispersion composition for color filter of the present invention contains C.I. Pigment Violet 29 in an amount of 5 to 50% by mass based on the total mass of the C.I. Pigment Red 179 and the C.I. Pigment Yellow 139.

By containing C.I. Pigment Violet 29 in a specific amount, the film thickness at the above-mentioned specific chromaticity coordinates can be more appropriately controlled to be 3 μm or less.

The red pigment dispersion composition for color filter of the present invention may contain a red pigment, an orange pigment, and a yellow pigment used in a conventional red pigment dispersion composition within a range not impairing the effects of the present invention.

Examples of such pigments include C.I. Pigment Red 177, C.I. Pigment Red 254, and C.I. Pigment Red 291.

(Pigment dispersant)

The red pigment dispersion composition for color filter of the present invention preferably contains a pigment dispersant, a pigment dispersing aid, an alkali-soluble resin, and an organic solvent.

First, the pigment dispersant will be described.

As the pigment dispersant, a polymer pigment dispersant having a basic group which has been conventionally used in the field of color filters can be used.

Examples of the polymer pigment dispersant having a basic group include the following pigment dispersants.

(1) A reaction product of an amino group and/or an imino group of a polyamine compound (e.g., poly(lower) alkyleneamines such as polyallylamine, polyvinylamine, and polyethylenepolyimine) and at least one selected from the group consisting of polyesters, polyamides, and polyesteramides having a free carboxyl group.

(2) A carbodiimide compound having in its molecule at least one side chain selected from the group consisting of a polyester side chain, a polyether side chain and a polyacrylic acid side chain and a basic nitrogen-containing group.

(3) Reaction products of low molecular weight amine compounds such as poly(lower) alkylene imine and methyliminodipropylamine with polyesters having free carboxyl groups.

(4) A reaction product formed by reacting alcohols such as methoxypolyethylene glycol, polyesters having one hydroxyl group such as caprolactone polyester, compounds having 2 to 3 isocyanate-reactive functional groups, aliphatic or heterocyclic hydrocarbon compounds having isocyanate-reactive functional groups and tertiary amino groups, and isocyanate groups of polyisocyanate compounds in sequence.

(5) A reaction product obtained by reacting a polyisocyanate compound and a hydrocarbon compound having an amino group with a polymer of an acrylate having an alcoholic hydroxyl group.

(6) A reaction product formed by adding a low molecular weight amine compound to a polyether chain.

(7) A reaction product formed by reacting a compound having an amino group with a compound having an isocyanate group.

(8) A reaction product obtained by reacting a linear polymer having a free carboxyl group and an organic amine compound having one secondary amino group with a polyepoxide compound.

(9) A reaction product of a polycarbonate compound having a functional group reactive with an amino group at one terminal and a polyamine compound.

(10) A copolymer of at least one methacrylate or acrylate selected from methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, octadecyl methacrylate, benzyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octadecyl acrylate, benzyl acrylate and the like, and at least one polymerizable monomer containing a basic group selected from acrylamide, methacrylamide, N-hydroxymethylamide, vinylimidazole, vinylpyridine, a monomer having an amino group and a polycaprolactone skeleton, and at least one selected from styrene, a styrene derivative, and other polymerizable monomers.

(11) Nitrogen-containing acrylic block copolymers composed of a block having a basic group such as a tertiary amino group or a quaternary ammonium base and a block having no basic functional group.

(12) A pigment dispersant obtained by subjecting a polycarbonate compound to a polyallylamine through a Michael addition reaction.

(13) Carbodiimide compounds each having at least one polybutadiene chain and a basic nitrogen-containing group.

(14) A carbodiimide compound having at least one side chain having an amide group and at least one basic nitrogen-containing group in the molecule.

(15) A polyurethane compound having a structural unit having an ethylene oxide chain and a propylene oxide chain and having an amino group quaternized by a quaternizing agent.

(16) A compound obtained by reacting an isocyanate group of an isocyanate compound having an isocyanurate ring in its molecule with an active hydrogen group of a compound having an active hydrogen group in its molecule and having a carbazole ring and/or an azobenzene skeleton, wherein the number of carbazole rings and azobenzene skeletons in the molecule of the compound is 15 to 85% relative to the total number of isocyanate groups derived from the isocyanate compound having an isocyanurate ring and urethane bonds and urea bonds generated by the reaction of the isocyanate group and the active hydrogen group; etc.

The above-mentioned pigment dispersants may be used alone or in combination of two or more.

From the viewpoint of properly exerting pigment dispersibility, the pigment dispersant is preferably a nitrogen-containing acrylic resin-based polymer pigment dispersant, and more preferably an acrylic block copolymer composed of a block having a basic group such as an amino group or a quaternary ammonium base and a block having no basic functional group.

As the above-mentioned nitrogen atom-containing acrylic resin-based polymer pigment dispersant, it is further preferred that it comprises at least one of an A-B block copolymer and a B-A-B block copolymer composed of an A block having at least one of a quaternary ammonium base and an amino group in a side chain and a B block having neither a quaternary ammonium base nor an amino group.

In the pigment dispersion composition for color filter of the present invention, the content of the pigment dispersant is preferably 1 to 100 parts by mass, more preferably 1 to 60 parts by mass, based on 100 parts by mass of the pigment.

If the content of the pigment dispersant is less than 1 part by mass based on 100 parts by mass of the pigment, the pigment dispersion effect may be reduced. On the other hand, if the content exceeds 100 parts by mass based on 100 parts by mass of the pigment, the developability may be reduced.

(Pigment dispersing aid)

As the pigment dispersing aid, those conventionally used in the field of color filters can be used, and from the viewpoint of appropriately exhibiting the dispersibility of the pigment, a sulfonic acid group-containing pigment dispersing aid is preferred.

As the above-mentioned sulfonic acid group-containing pigment dispersing aid, a sulfonated product of a compound having an azo group and a naphthol skeleton is more preferable.

The sulfonic acid group-containing pigment dispersing aid can appropriately increase the brightness of a color filter obtained using the red pigment dispersion composition for color filter of the present invention by containing a compound having the azo group and a naphthol skeleton, and can improve dispersibility.

Examples of the compound having the above-mentioned azo group and naphthol skeleton include C.I. Pigment Red 2, 112, 188, and C.I. Pigment Brown 25.

By sulfonating the compound having the above-mentioned azo group and a naphthol skeleton, a sulfonated product of the compound having the above-mentioned azo group and a naphthol skeleton can be obtained.

The sulfonation method is not particularly limited, and a well-known method can be used.

Among them, from the viewpoint of better improving the brightness of the color filter obtained using the red pigment dispersion composition for color filter of the present invention, a sulfonate of C.I. Pigment Red 188 is preferred, and from the viewpoint of appropriately improving the dispersion stability of the above-mentioned pigment and improving the contrast of the color filter obtained using the red pigment dispersion composition for color filter of the present invention, a sulfonate of C.I. Pigment Red 2 is more preferred.

The above-mentioned pigment dispersing aids may be used alone or in combination of two or more.

The content of the pigment dispersing aid is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass, based on the total mass of the red pigment dispersion composition for color filter.

(Alkali soluble resin)

There is no particular limitation on the alkali-soluble resin, and any alkali-soluble resin that has been used can be used. Preferably, the alkali-soluble resin acts as a binder for the pigment and is soluble in the developer (preferably an alkaline developer) used in the development process when manufacturing the color filter.

The alkali-soluble resin may be a random copolymer or a block copolymer.

Among the above-mentioned alkali-soluble resins, those having a carboxyl group are preferred, and copolymers composed of an ethylenically unsaturated monomer having one or more carboxyl groups and other copolymerizable ethylenically unsaturated monomers are more preferred.

Specific examples of the alkali-soluble resin include copolymers of ethylenically unsaturated monomers having a carboxyl group, such as acrylic acid and methacrylic acid, and at least one ethylenically unsaturated monomer selected from the group consisting of monomers and oligomers copolymerizable with the ethylenically unsaturated monomer having a carboxyl group, such as styrene, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, allyl acrylate, allyl methacrylate, benzyl acrylate, benzyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, glycerol monoacrylate, glycerol methacrylate, N-phenylmaleimide, polystyrene macromonomers, polymethyl methacrylate macromonomers, and carbocyclic diacrylate.

However, it is preferred not to use N-vinyl pyrrolidone or a monomer containing a sulfur element. In addition, the alkali-soluble resin may have a photopolymerizable functional group.

The acid value of the alkali-soluble resin is preferably 5 to 250 mgKOH/g, more preferably 10 to 200 mgKOH/g, and further preferably 60 to 150 mgKOH/g, from the viewpoint of development characteristics.

In the present invention, the acid value is a theoretical acid value, which is a value arithmetically determined based on the ethylenically unsaturated monomer having a carboxyl group and its content.

In general, from the viewpoint of development characteristics and solubility in organic solvents, the weight average molecular weight of the alkali-soluble resin is preferably 1,000 to 100,000, more preferably 3,000 to 50,000, and even more preferably 7,000 to 20,000.

In this specification, the weight average molecular weight of the alkali-soluble resin is a weight average molecular weight in terms of polystyrene obtained by GPC. The measurement can be performed using Water 2690 (manufactured by Waters Corporation) as an apparatus and PLgel 5 μm MIXED-D (manufactured by Agilent Technologies) as a column.

The content of the alkali-soluble resin is preferably 1 to 200 parts by mass, more preferably 10 to 150 parts by mass, based on 100 parts by mass of the pigment.

When the content of the alkali-soluble resin is less than 1 part by mass relative to 100 parts by mass of the pigment, the developing characteristics may be reduced. On the other hand, if the content of the alkali-soluble resin exceeds 200 parts by mass relative to 100 parts by mass of the pigment, the colorant concentration is relatively reduced, so it may be difficult to achieve the target color concentration (color density) as a film.

The alkali-soluble resin preferably does not contain any of primary, secondary, and tertiary amino groups, and further preferably does not contain a quaternary ammonium group.

Furthermore, it is more preferable that the compound has no basic group.

(Other resins)

The red pigment dispersion composition for color filter of the present invention may contain other resins.

As the other resin, it is preferable to use a resin having a higher transmittance in the entire wavelength region of 400 to 700 nm in the visible light region.

As such a resin, a thermosetting resin, a thermoplastic resin, an alkali-soluble resin other than the above resins can be used, and the following photopolymerizable compounds can also be used.

The total amount of the other resins used is preferably 5 to 94% by mass, more preferably 20 to 50% by mass, based on the total solid content of the red pigment dispersion composition for color filter.

Examples of the thermosetting resin and thermoplastic resin include butyral resin, styrene-maleic acid copolymer, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyurethane resin, phenol resin, polyester resin, acrylic resin, alkyd resin, styrene resin, polyamide resin, rubber resin, cyclized rubber, epoxy resin, cellulose, polybutadiene, polyimide resin, benzoguanamine resin, melamine resin, urea resin, and the like.

Furthermore, a photopolymerizable resin described in the pigment dispersion resist composition for color filter described later may be blended as necessary.

(Organic Solvent)

As the organic solvent, an organic solvent conventionally used in the field of liquid crystal color filter resists can be preferably used.

Specifically, the organic solvent includes ester organic solvents, ether organic solvents, ether ester organic solvents, ketone organic solvents, aromatic hydrocarbon organic solvents, nitrogen-containing organic solvents, etc. having a boiling point of 100 to ²²⁰ °C at normal pressure (1.013×10 2 kPa).

If the organic solvent contains a large amount of an organic solvent having a boiling point exceeding 220° C., when the coating formed by applying the red pigment dispersion composition for color filters or the red pigment dispersion anti-etching composition for color filters described later is pre-baked, the organic solvent cannot be fully evaporated and remains in the dried coating, and there is a possibility that the heat resistance of the dried coating will be reduced.

Furthermore, if a large amount of an organic solvent having a boiling point of less than 100° C. is contained as the organic solvent, uniform coating becomes difficult, and there is a possibility that a coating film having excellent surface smoothness cannot be obtained.

Specific examples of the organic solvent include ether-based organic solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, and diethylene glycol methyl ethyl ether; ether-based organic solvents such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; methyl isobutyl ketone, cyclohexanone, 2-heptanone, δ -Butyrolactone and other ketone organic solvents; 2-hydroxypropionic acid methyl ester, 2-hydroxypropionic acid ethyl ester, 2-hydroxy-2-methylpropionic acid ethyl ester, 3-methyl-3-methoxybutyl propionate, 3-methoxypropionic acid methyl ester, 3-methoxypropionic acid ethyl ester, 3-ethoxypropionic acid methyl ester, 3-ethoxypropionic acid ethyl ester, ethoxyacetic acid ethyl ester, hydroxyacetic acid ethyl, n-pentyl formate and other ester organic solvents; methanol, ethanol, isopropanol, butanol, diacetone alcohol and other alcohol solvents; N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide and other nitrogen-containing organic solvents, etc.

These organic solvents may be used alone or in combination of two or more.

Among the above-mentioned organic solvents, from the viewpoints of solubility, dispersibility, coating properties, etc., diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, cyclohexanone, 2-heptanone, ethyl 2-hydroxypropionate, 3-methyl-3-methoxybutyl propionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, n-pentyl formate, etc. are preferred, and propylene glycol monomethyl ether acetate is more preferred.

From the viewpoint of improving the solubility, pigment dispersibility, coating properties, etc. of the alkali-soluble resin, the content of the organic solvent is preferably 30 to 80% by mass, more preferably 35 to 75% by mass, based on the total mass of the red pigment dispersion composition for color filters.

(Method for producing red pigment dispersion composition for color filter)

As a method for producing the red pigment dispersion composition for color filter of the present invention, the red pigment dispersion composition for color filter of the present invention can be obtained by adding the above-mentioned various components, mixing and grinding.

As a method of adding the above-mentioned various components, for example, a plurality of pigment dispersions containing one type of pigment may be prepared, and then the prepared pigment dispersions may be mixed to prepare a red pigment dispersion composition for a color filter.

The red pigment dispersion composition for color filter of the present invention is preferably used for a color filter of an image display device including a light source including quantum dots.

As the quantum dots, for example, those disclosed in Japanese Unexamined Patent Application Publication No. 2013-539598 can be used.

<Red pigment dispersion resist composition for color filter>

The red pigment dispersion resist composition for color filter can be obtained by adding an alkali-soluble resin, a photopolymerizable compound, a photopolymerization initiator, an organic solvent, and, if necessary, additives in addition to the red pigment dispersion composition for color filter of the present invention.

(Red pigment dispersion composition for color filter)

The red pigment dispersion resist composition for color filter contains the red pigment dispersion composition for color filter of the present invention.

The content of the red pigment dispersion composition for color filter is preferably 30 to 80% by mass, more preferably 40 to 75% by mass, based on the total mass of the red pigment dispersion resist composition for color filter of the present invention.

(Alkali soluble resin)

As the alkali-soluble resin, the alkali-soluble resins described in the above-mentioned red pigment dispersion composition for color filter of the present invention can be appropriately selected and used.

The content of the alkali-soluble resin is preferably 1 to 35% by mass, more preferably 3 to 30% by mass, based on the total mass of the red pigment dispersion resist composition for color filter of the present invention.

(Photopolymerizable compound)

Examples of the photopolymerizable compound include monomers and oligomers having one or more photopolymerizable unsaturated bonds in the molecule. The photopolymerizable unsaturated bond is an unsaturated bond that can be polymerized by the action of free radicals or cations generated when the photopolymerization initiator described later is decomposed by active energy rays such as ultraviolet rays and electron beams.

Examples of the monomer having one photopolymerizable unsaturated bond in the molecule include: alkyl methacrylates or alkyl acrylates such as methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl methacrylate, methyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; aralkyl methacrylates or aralkyl acrylates such as benzyl methacrylate and benzyl acrylate; alkoxyalkyl methacrylates or alkoxyalkyl acrylates such as butoxyethyl methacrylate and butoxyethyl acrylate; N-methacrylate ,N-dimethylaminoethyl ester, N,N-dimethylaminoethyl acrylate and other aminoalkyl methacrylates or aminoalkyl acrylates; methacrylates or acrylates of polyalkylene glycol alkyl ethers such as diethylene glycol ethyl ether, triethylene glycol butyl ether and dipropylene glycol methyl ether; methacrylates or acrylates of polyalkylene glycol aryl ethers such as hexaethylene glycol phenyl ether; isobornyl methacrylate or isobornyl acrylate; glyceryl methacrylate or glyceryl acrylate; 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate, etc.

In this specification, (meth)acrylate means acrylate and methacrylate.

Examples of the monomer having two or more photopolymerizable unsaturated bonds in one molecule include bisphenol A dimethacrylate, 1,4-butanediol dimethacrylate, 1,3-butanediol dimethacrylate, diethylene glycol dimethacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, and dipentaerythritol tetramethacrylate. Acrylate, dipentaerythritol hexamethacrylate, dipentaerythritol pentamethacrylate, bisphenol A diacrylate, 1,4-butanediol diacrylate, 1,3-butanediol diacrylate, diethylene glycol diacrylate, glycerol diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, tetraethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, etc.

The above-mentioned photopolymerizable compounds may be used alone or in combination of two or more.

The content of the photopolymerizable compound is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass, based on the total mass of the red pigment dispersion resist composition for color filter of the present invention.

(Photopolymerization Initiator)

The photopolymerization initiator is not particularly limited as long as it is a photopolymerization initiator that can generate free radicals or cations by irradiation with active energy rays such as ultraviolet rays and electron beams, and examples thereof include benzophenone, N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, benzil, 2,2-diethoxyacetophenone, benzoin, benzoin methyl ether, benzoin isobutyl ether, benzil dimethyl ketal, α-hydroxyisobutyl benzophenone (α-hydroxyisobutyl benzophenone), and the like. tylphenone), thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexyl phenyl ketone, tert-butyl anthraquinone, 1-chloroanthraquinone, 2,3-dichloroanthraquinone, 3-chloro-2-methylanthraquinone, 2-ethyl anthraquinone, 1,4-naphthoquinone, 1,2-benzanthraquinone, 1,4-dimethylanthraquinone, 2-phenylanthraquinone, 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropane-1-one, 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone, triazine-based photopolymerization initiators, etc.

The above-mentioned photopolymerization initiators may be used alone or in combination of two or more.

The content of the photopolymerization initiator is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass, based on the total mass of the red pigment dispersion resist composition for color filter of the present invention.

(Organic Solvent)

As the organic solvent, those described in the above-mentioned red pigment dispersion composition for color filter of the present invention may be appropriately selected and used.

The content of the organic solvent is preferably 1 to 40% by mass, more preferably 5 to 35% by mass, based on the total mass of the red pigment dispersion resist composition for color filter of the present invention.

(Other additives)

The red pigment dispersion resist composition for color filter of the present invention may contain additives within a range not impairing the effects of the present invention.

Examples of the additives include various additives such as a thermal polymerization inhibitor, a silane coupling agent, a titanate coupling agent, an ultraviolet absorber, and an antioxidant.

(Method for producing red pigment dispersion resist composition for color filter)

The method for producing the red pigment dispersion resist composition for color filter of the present invention is not particularly limited, and the composition can be obtained by mixing and grinding the above-mentioned materials by a well-known method.

＜Color Filter＞

The red pigment dispersion resist composition for color filter of the present invention can be used to form a color filter.

The color filter comprises a red filter segment, a green filter segment, and a blue filter segment, and the red filter segment is formed using the red pigment dispersion resist composition for a color filter of the present invention.

The green filter segment and the blue filter segment can be formed using well-known materials and methods.

The color filter formed using the red pigment dispersion resist composition for a color filter of the present invention can be formed by appropriately selecting and using a well-known method such as a printing method or a photolithography method.

＜Display device＞

The above color filter can be used as a display device.

The display device is not particularly limited as long as it includes the color filter of the present invention, and examples thereof include well-known liquid crystal display devices and touch panels.

The light source of the display device preferably includes the quantum dots.

Effects of the Invention

The present invention can provide a red pigment dispersion composition for color filters that can form a coating film that can achieve excellent color reproducibility even in a thin film when quantum dots are used as a backlight source.

DETAILED DESCRIPTION

The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples. In addition, unless otherwise specified, "%" means "mass %" and "part" means "mass part".

The materials used in Examples and Comparative Examples are as follows.

＜Pigment＞

(PR179): C.I. Pigment Red 179

(PV29): C.I. Pigment Violet 29

(PY139): C.I. Pigment Yellow 139

(PR177): C.I. Pigment Red 177

(PR254): C.I. Pigment Red 254

(PR291): C.I. Pigment Red 291

＜Pigment dispersant＞

(Nitrogen atom-containing acrylic block copolymer)

Tertiary amino group-containing acrylic block copolymer (LP-N21116, manufactured by BYK Chemical Co., Ltd.)

＜Pigment dispersing aid＞

(PR2S)

30 ml of concentrated sulfuric acid was placed in a 100 ml conical flask, and 10 g of C.I. Pigment Red 2 was added while stirring with a magnetic stirrer, and stirred at room temperature for 30 minutes. A mixture of 50 g of water and 50 g of ice was placed in a 1 L beaker, and the above reactants were poured into the ice water and stirred with a magnetic stirrer for 30 minutes. The mixture was filtered and washed with water under reduced pressure, and the obtained solid was dried to prepare a pigment dispersing aid containing a sulfonic acid group (sulfonated product of C.I. Pigment Red 2, PR2S).

<Alkali-soluble resin>

(BMA/MAA copolymer)

Butyl methacrylate/methacrylic acid copolymer (PHORET ZAH110, manufactured by Soken Chemical Co., Ltd., solid content 35%)

＜Organic solvents＞

(PGMEA): Propylene glycol monomethyl ether acetate

＜Photopolymerizable compounds＞

(DPHA): Dipentaerythritol hexaacrylate (A9530, manufactured by Shin-Nakamura Chemical Co., Ltd.)

＜Photopolymerization initiator＞

(Irgacure 369): 2-(Dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone

<Preparation of red pigment dispersion composition for color filter>

Pigment dispersions 1 to 6 were prepared by adding the above-mentioned various components in the blending amounts described in Table 1.

Thereafter, the pigment dispersions 1 to 6 were mixed and ground at the mass ratios described in Table 2 to prepare red pigment dispersion compositions for color filters of Examples and Comparative Examples.

[Table 1]

[Table 2]

<Preparation of red pigment dispersion resist composition for color filter>

Various materials were added so as to give the above components the compositions shown in Table 3, and the mixture was uniformly mixed using a high-speed stirrer and then filtered using a membrane filter having a pore size of 3 μm to prepare red pigment dispersion resist compositions for color filters of Examples and Comparative Examples.

[Table 3]

(Viscosity)

The viscosity at 25° C. of the red pigment dispersion resist composition for color filters prepared in Examples and Comparative Examples was measured using an E-type viscometer (R100 type viscometer, model number RE100L manufactured by Toki Sangyo Co., Ltd.).

(Dispersion stability)

The red pigment dispersion resist compositions for color filters prepared in the examples and comparative examples were placed in glass bottles and sealed tightly, and the state after being stored for one month at 40°C, 5°C, and room temperature (23°C) was evaluated according to the following evaluation criteria. The results are shown in Table 4.

○: The viscosity change rate before and after storage is less than 10%

×: The viscosity change rate before and after storage exceeds 10%

(Film thickness of coating)

The pigment dispersion resist compositions for color filters of the embodiment and the comparative example were applied to a glass substrate respectively by a spin coater and pre-baked at 100°C for 3 minutes. At this time, two coated plates were prepared for each resist composition so as to form two coating films with different chromaticity x (value after post-baking described later). That is, the thickness was changed by changing the rotation speed of the spin coater so that the chromaticity x of one of the two coated plates was always less than 0.6800, and the chromaticity x of the other was always greater than 0.6800.

Next, each coated plate was exposed with a high-pressure mercury lamp and then post-baked at 230°C for 30 minutes. Thereafter, three scratches were made on the coated plate with a knife within a range of 3 mm, and the depth was measured by scanning with a surface roughness meter (KLA-Tencor Corporation, surface profiler ALPHA-STEP IQ). The average value of the three points was calculated as the film thickness of the coating. For each coating, an approximate straight line (calibration curve) was obtained from the measured values of the two coated plates prepared in the above manner, and the film thickness when the chromaticity x was 0.6800 was calculated, and the film thickness was adopted as the embodiment and the comparative example.

(Brightness of coating film)

For each coated plate of the pigment dispersion resist composition for color filters obtained by the above method, the brightness Y was measured using a spectrophotometer (manufactured by Shimadzu Corporation, UV-2500PC, C light source 2° field of view). For each coating formed on the above-mentioned coated plate, an approximate straight line (calibration curve) was obtained from the brightness values Y of the two coated plates prepared in the above manner, and the value of chromaticity x of 0.6800 was calculated, and the brightness value Y of the embodiment and the comparative example was adopted.

(y value of coating film)

The chromaticity y value of each color filter pigment dispersion resist composition coated plate obtained by the above method was measured using a spectrophotometer (manufactured by Shimadzu Corporation, UV-2500PC, C light source 2° field of view). For each coating formed on the above-mentioned coated plate, an approximate straight line (calibration curve) was obtained from the chromaticity y of the two coated plates prepared in the above manner, and the y value when the chromaticity x was 0.6800 was calculated and adopted as the y value of the embodiment and the comparative example.

(Transmittance of coating film)

For each color filter pigment dispersion resist composition coated plate obtained by the above method, the transmittance was measured at intervals of 10 nm from a wavelength of 590 nm to 670 nm using a spectrophotometer (manufactured by Shimadzu Corporation, UV-2500PC, light source C, 2° field of view).

For each of the wavelengths described above, an approximate straight line (calibration curve) was obtained from the transmittance values of the two coated plates prepared in the above manner, and the chromaticity x was calculated to be 0.6800, which was adopted as the transmittance of the Example and the Comparative Example.

In addition, [T(630)-T(600)]/[T(600)-T(590)] was calculated when the transmittance at the wavelength a n was set to T(a). The results are shown in Table 4.

[Table 4]

Industrial Applicability

The red pigment dispersion composition for color filters of the present invention can form a coating film that can achieve excellent color reproducibility even in a thin film when quantum dots are used as a backlight light source, and is therefore suitable as a red pigment dispersion resist composition for color filters used in color filters of liquid crystal display devices, touch panels, etc.

Claims (8)

1. A red pigment dispersion composition for a color filter, wherein,

When a coating film is formed under the condition that the chromaticity (x, y) value in the XYZ color system measured by using a C light source in the CIE1931 color system as a light emitting element is in the chromaticity range of x= 0.6700 to 0.6900 and y= 0.3100 to 0.3300, the film thickness is 3 μm or less; when the transmittance at the wavelength anm is set to be T (a), the [ T (630) -T (600) ]/[ T (600) -T (590) ] of the coating film is 1.9 or more;

The red pigment dispersion composition for a color filter contains c.i. pigment red 179 and c.i. pigment yellow 139 in a mass ratio of c.i. pigment red 179 mass/c.i. pigment yellow 139 mass=95/5 to 40/60;

c.i. pigment violet 29 is contained in an amount of 5 to 50 mass% relative to the total mass of c.i. pigment red 179 and c.i. pigment yellow 139.

2. The red pigment-dispersion composition for a color filter according to claim 1, which comprises a pigment dispersant, a pigment-dispersion aid, an alkali-soluble resin, and an organic solvent.

3. The red pigment-dispersion composition for a color filter according to claim 2, wherein,

The pigment dispersant is a high molecular pigment dispersant containing an alkaline group.

4. The red pigment-dispersion composition for a color filter according to claim 3, wherein,

The polymer pigment dispersant containing basic groups is an acrylic block copolymer containing nitrogen atoms.

5. The red pigment dispersion composition for a color filter according to claim 2, wherein the pigment dispersion aid is a sulfonic acid group-containing pigment dispersion aid.

6. The red pigment dispersion composition for a color filter according to claim 3, wherein the pigment dispersion aid is a sulfonic acid group-containing pigment dispersion aid.

7. The red pigment dispersion composition for a color filter according to claim 4, wherein the pigment dispersion aid is a sulfonic acid group-containing pigment dispersion aid.

8. The red pigment dispersion composition for a color filter according to any one of claims 1 to 7, which is used for a color filter of an image display device provided with a light source including quantum dots.