JP2020093994A - Azo compound-containing coloring composition, color filter coloring agent, and color filter - Google Patents

Abstract

To provide: a coloring composition and a color filter coloring agent that contain an azo compound with good coloring (color gamut, luminance, contrast etc.) and excellent solubility; and a color filter using the color filter coloring agent.SOLUTION: The azo compound is represented by general formula (1) in the figure.SELECTED DRAWING: Figure 1

Description

The present invention relates to an azo compound, a coloring composition containing the azo compound, a colorant for a color filter using the coloring composition, and a color filter using the coloring agent.

Color filters used in liquid crystal displays and electroluminescence (EL) display devices are manufactured by laminating a coloring layer on a translucent substrate such as glass by a dyeing method, a pigment dispersion method, a printing method, an electrodeposition method or the like. To be done. The colorant used for the colored layer is roughly classified into a pigment and a dye, and a pigment generally excellent in heat resistance and light resistance is widely used (for example, Patent Documents 1 to 3). However, it is known that a color filter using a pigment has a depolarizing effect due to reflection/scattering of transmitted light on the surface of the pigment particles in the filter, and thus the contrast ratio of the color liquid crystal display device is lowered.

In order to improve such a problem of the decrease in contrast ratio, a method of using only a dye as a colorant, a method of using a dye and a pigment together, and the like have been proposed (for example, Patent Documents 4 to 8). Since the dye is soluble in the solvent, the color filter using the dye has a better depolarizing effect than the case where only the pigment is used as the colorant, and has excellent spectral characteristics.

The azo compound is a kind of pigment having a wide variety of colors, and is often used as a pigment or a dye because of easy availability of raw materials and a simple manufacturing process (Patent Document 9). Also in the field of color filters, studies have been conducted to improve color characteristics by using azo compounds (Patent Documents 10 and 11). In particular, there is a demand for a coloring composition for a color filter having high brightness and contrast, which is said to be effective for improving the brightness, and makes the rising slope of the transmission spectrum in a specific wavelength region more sharp (rapid). Studies have been made (Patent Documents 12 and 13).

It is known that in an azo compound, the tautomeric structure is biased to one side or the absorption spectrum is changed due to steric hindrance depending on the kind or position of the substituent on the phenyl group adjacent to the azo group (non- Patent Document 1). In order to sharpen the spectrum of an azo compound (= make the inclination of the transmission spectrum at a specific wavelength sharper and steeper), it is possible to suppress structural changes such as tautomerism in the possible resonance structure of the compound. It is considered more effective to suppress fluctuations in excitation energy due to fluctuations in the three-dimensional structure such as rotation. Further, the presence of these substituents in excess of the required size reduces the size of the conjugated system, invites a spectrum shift and a decrease in the absorption coefficient, and deteriorates the color characteristics of the dye.

JP, 2001-220520, A Japanese Patent Publication No. 2007-533802 JP 2012-12498 A JP, 2002-265834, A JP2012-207224A JP, 2010-254964, A JP, 2014-12814, A JP, 2014-59538, A JP, 2013-40240, A International Publication No. 2005-052074 JP-A-11-14824 JP, 2009-237462, A International Publication No. 2012-039361 JP, 10-36692, A

"Coloring Materials Association Magazine", 1980, Vol. 53, No. 12, p. 724-739

It is an object of the present invention to provide a coloring composition and a colorant for a color filter, which contain an azo compound having excellent color developability (color gamut, brightness, contrast, etc.) and excellent solubility. Another object of the present invention is to provide a color filter using the colorant for a color filter.

As a result of intensive studies, the inventors of the present invention have found that an azo compound represented by the following general formula (1) has a sharp rising spectrum in a specific wavelength region and has good solubility. I found it. The present inventors have also found that a color filter having good color developability can be provided by using a coloring composition containing the azo compound as a colorant for a color filter, and completed the present invention. That is, the present invention is summarized below.

1. An azo compound represented by the following general formula (1).

[Wherein R ¹ and R ² are each independently
A linear or branched alkyl group having 1 to 20 carbon atoms, which may have a substituent,
A cycloalkyl group having 3 to 20 carbon atoms, which may have a substituent,
Represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent, or a heterocyclic group having 2 to 20 carbon atoms which may have a substituent,
They may be bonded to each other to form a ring.
R ^{3 to} R ⁵ are each independently
Hydrogen atom, halogen atom, hydroxyl group, nitro group, cyano group, carboxylic acid group, sulfonic acid group,
A linear or branched alkyl group having 1 to 20 carbon atoms, which may have a substituent,
A cycloalkyl group having 3 to 20 carbon atoms, which may have a substituent,
A linear or branched alkoxy group having 1 to 20 carbon atoms, which may have a substituent,
A cycloalkoxy group having 3 to 20 carbon atoms which may have a substituent, a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent,
An acyl group having 1 to 20 carbon atoms which may have a substituent,
An amino group having 0 to 20 carbon atoms, which may have a substituent,
Represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent, or a heterocyclic group having 2 to 20 carbon atoms which may have a substituent,
R ³ and R ⁴ may combine with each other to form a ring. ]

2. An azo compound in which R ¹ and R ² in the general formula (1) are linear or branched alkyl groups having 3 to 10 carbon atoms which may have a substituent.

3. An azo compound in which R ^{3 to} R ⁵ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an amino group, a carboxylic acid group or a sulfonic acid group in the general formula (1).

4. In the ultraviolet-visible transmission spectrum (wavelength side of 400 nm or longer) measured at 23 to 27° C. using a propylene glycol monomethyl ether acetate (PGMEA) solution having a concentration of the azo compound of 0.02 mmol/L,
Ratio of change amount (ΔT) of transmittance to change amount (Δλ) of wavelength in the range from wavelength λ (nm) where transmittance T is 30% to wavelength λ (nm) where transmittance T is 80% (Change rate of transmittance T)
An azo compound having (ΔT(%)/Δλ(nm)) of 2 (transmittance %/nm) or more.

5. An azo compound having a solubility of 3% by weight or more in propylene glycol monomethyl ether acetate (PGMEA) at 23 to 27°C.

6. A coloring composition containing the azo compound.

7. A colorant for a color filter, which contains the coloring composition.

8. A color filter using the colorant for a color filter.

The azo compound of the present invention has a sharp slope of the transmission spectrum (having a large rate of change in transmittance) in the wavelength region on the long wavelength side of 400 nm or more, and is excellent in color developability (color gamut, brightness, contrast, etc.), In addition, since it has excellent solubility, the coloring composition containing the azo compound is suitable as a colorant for a color filter.

It is a figure explaining the specific example of the ultraviolet visible transmission spectrum of the azo compound of this invention.

Embodiments of the present invention will be described in detail below. The present invention is not limited to the following embodiments and can be variously modified and implemented within the scope of the gist.

The azo compound represented by the general formula (1) will be described.

In the general formula (1), "1 carbon atom in the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent(s)" represented by R ¹ and R ² Specifically, "a straight-chain or branched alkyl group of 20" includes
Linear alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group and decyl group;
Examples thereof include branched alkyl groups such as isopropyl group, isobutyl group, s-butyl group, t-butyl group and isooctyl group.

In the general formula (1), “cycloalkyl group having 3 to 20 carbon atoms” in “cycloalkyl group having 3 to 20 carbon atoms which may have a substituent” represented by R ¹ and R ² Examples of "" include cycloalkyl groups such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group and cyclodecyl group.

In the general formula (1), the “aromatic having 6 to 20 carbon atoms” in the “aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent” represented by R ¹ and R ^2. Examples of the “heterocyclic group having 2 to 20 carbon atoms” in the “group hydrocarbon group” and the “heterocyclic group having 2 to 20 carbon atoms which may have a substituent” include a phenyl group, Aromatic hydrocarbon groups (or fused polycyclic aromatic groups) such as naphthyl group, biphenyl group, anthryl group (anthracenyl group), phenanthryl group, pyrenyl group, indenyl group, fluorenyl group, triphenylyl group, perylenyl group;
Pyridyl group, pyrimidinyl group, triazinyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, triazolyl group, quinolyl group, isoquinolyl group, naphthyridinyl group, indolyl group, benzimidazolyl group, carbazonyl group, carborinyl group, acridinyl group, phenanthrolinyl group , Furanyl group, benzofuranyl group, dibenzofuranyl group, thienyl group, benzothienyl group, dibenzothienyl group, oxazolyl group, benzoxazolyl group, thiazolyl group, benzothiazolyl group and other heterocyclic groups (or heteroaromatic hydrocarbon groups) ), etc.

In the general formula (1), represented by R ¹ and R ² ,
“A linear or branched alkyl group having 1 to 20 carbon atoms having a substituent”,
"C3-C20 cycloalkyl group having a substituent",
The “substituent” in the “aromatic hydrocarbon group having 6 to 20 carbon atoms having a substituent” or the “heterocyclic group having 2 to 20 carbon atoms having a substituent” is specifically a fluorine atom. Halogen atoms such as chlorine, bromine and iodine atoms;
Hydroxyl group; Nitro group; Cyano group; Amino group;
_A carboxylic acid group represented by —COOH or —COOM _A , or
_A sulfonic acid group represented by —SO ₃ H or —SO ₃ M _A (wherein M _A represents an alkali metal atom such as lithium, sodium, potassium, or cesium, and when a plurality of M _A exists, the same or different) And they are preferably the same).
A linear alkyl group having 1 to 19 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group and a decyl group;
A branched alkyl group having 3 to 19 carbon atoms, such as isopropyl group, isobutyl group, s-butyl group, t-butyl group, isooctyl group;
A cycloalkyl group having 3 to 19 carbon atoms such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and a cyclooctyl group;
Methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, nonyloxy group, decyloxy group and the like linear alkoxy group having 1 to 19 carbon atoms; iso A branched alkoxy group having 3 to 19 carbon atoms such as a propoxy group, an isobutoxy group, an s-butoxy group, a t-butoxy group, an isooctyloxy group;
A cycloalkoxy group having 3 to 19 carbon atoms such as a cyclopropoxy group, a cyclobutoxy group, a cyclopentyloxy group and a cyclohexyloxy group;
Vinyl group, 1-propenyl group, allyl group, 1-butenyl group, 2-butenyl group, 1-pentenyl group, 1-hexenyl group, isopropenyl group, isobutenyl group, or the number of carbon atoms to which a plurality of these alkenyl groups are bonded 2 to 19 linear or branched alkenyl groups,
Formyl group, acetyl group, propionyl group, isopropionyl group, butyroyl group, isobutyroyl group, acryl group, cyclohexanoyl group, cyclohexanoyl group, benzoyl group, methylbenzoyl group, phenylacetyl group and the like having 1 to 19 carbon atoms An acyl group of
Methylamino group, dimethylamino group, ethylamino group, diethylamino group, methylethylamino group, propylamino group, isopropylamino group, dipropylamino group, diisopropylamino group, methylpropylamino group, butylamino group, 2-ethylhexylamino group An amino group having 1 to 19 carbon atoms such as a group;
An aromatic hydrocarbon group having 6 to 19 carbon atoms such as a phenyl group, a naphthyl group, a biphenyl group, an anthryl group, a phenanthryl group, a pyrenyl group, a triphenylenyl group, an indenyl group, a fluorenyl group or a condensed polycyclic aromatic group;
Pyridyl group, pyrimidinyl group, triazinyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, triazolyl group, quinolyl group, isoquinolyl group, naphthyridinyl group, indolyl group, benzimidazolyl group, carbazonyl group, carborinyl group, acridinyl group, phenanthrolinyl group , A furanyl group, a benzofuranyl group, a dibenzofuranyl group, a thienyl group, a benzothienyl group, a dibenzothienyl group, an oxazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, or another heterocyclic group having 2 to 19 carbon atoms, And so on. Only one of these “substituents” may be contained, a plurality of them may be contained, and when a plurality of these “substituents” are contained, they may be the same or different from each other. Further, these “substituents” may further have the substituents exemplified above. In addition, when a "substituent" contains a carbon atom, the carbon atom is the above-mentioned "C1-20", "C3-20", "C6-20", "C". It is included in the number 2 to 20". Further, these "substituents" may be bonded to each other by adjacent substituents, and their rings are a single bond or a bond through any atom of a nitrogen atom, an oxygen atom or a sulfur atom. It may form a ring.

In the general formula (1), as R ¹ and R ² , a linear or branched alkyl group having 3 to 10 carbon atoms which may have a substituent is preferable, and R ¹ and R ² have a substituent. A straight-chain or branched alkyl group having 3 to 8 carbon atoms is more preferable.

In the general formula (1), the combination of R ¹ and R ² may be the same or different. R ¹ and R ² may be bonded to each other to form a ring, or may be a single bond or a bond formed through a nitrogen atom, an oxygen atom or a sulfur atom. May be. The ring formed in that case is preferably a 5-membered ring or a 6-membered ring.

In the general formula (1), examples of the “halogen atom” represented by R ^{3 to} R ⁵ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The "halogen atom" is preferably a fluorine atom, a chlorine atom or a bromine atom.

In the general formula (1), the “carboxylic acid group” or “sulfonic acid group” represented by R ^{3 to} R ⁵ is specifically a carboxylic acid group represented by —COOH or —COOM _A , or
It represents a sulfonic acid group represented by —SO ₃ H or —SO ₃ M _A. However, M _A represents an alkali metal atom such as lithium, sodium, potassium, or cesium. In addition, it has the same meaning as the “carboxylic acid group” or “sulfonic acid group” described as the “substituent” which R ¹ and R ² may have.

Represented by R ^{3 to} R ⁵ in the general formula (1),
“A linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent”,
“A cycloalkyl group having 3 to 20 carbon atoms which may have a substituent”,
As the "aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent" or "heterocyclic group having 2 to 20 carbon atoms which may have a substituent",
In the above general formula (1), the same groups as those represented by R ¹ and R ² can be mentioned.

In the general formula (1), “a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent” represented by R ^{3 to} R ⁵ or “having a substituent” As the "linear or branched alkoxy group having 1 to 20 carbon atoms" or "cycloalkoxy group having 3 to 20 carbon atoms" in the "cycloalkoxy group having 3 to 20 carbon atoms which may be present" Specifically, a linear alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group and a decyloxy group;
A branched alkoxy group such as an isopropoxy group, an isobutoxy group, a s-butoxy group, a t-butoxy group, an isooctyloxy group;
And cycloalkoxy groups such as cyclopropoxy group, cyclobutoxy group, cyclopentyloxy group and cyclohexyloxy group;

In the general formula (1), "2 carbon atoms in the "linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" represented by R ^{3 to} R ⁵ " ~20 straight-chain or branched alkenyl groups" are vinyl, 1-propenyl, allyl, 1-butenyl, 2-butenyl, 1-pentenyl, 1-hexenyl, isopropenyl. , An isobutenyl group, or a linear or branched alkenyl group having a plurality of these alkenyl groups bonded to each other.

In the general formula (1), as the “acyl group having 1 to 20 carbon atoms” in the “acyl group having 1 to 20 carbon atoms which may have a substituent” represented by R ^{3 to} R ^5. Is a formyl group, acetyl group, propionyl group, isopropionoyl group, butyroyl group, isobutyroyl group, pentanoyl group, hexanoyl group, acrylyl group, cyclohexanoyl group, cycloheptanoyl group, benzoyl group, methylbenzoyl group, phenylacetyl group. Group, naphthanoyl group, and the like.

In the general formula (1), "amino group having 0 to 20 carbon atoms" in "amino group having 0 to 20 carbon atoms which may have a substituent" represented by R ^{3 to} R ^5. As, amino group, methylamino group, dimethylamino group, ethylamino group, diethylamino group, methylethylamino group, propylamino group, dipropylamino group, methylpropylamino group, ethylpropylamino group, butylamino group, dibutyl Examples thereof include an amino group, a pentanylamino group, a propenylamino group, a butenylamino group, a cyclohexylamino group, a dicyclohexylamino group, a phenylamino group, a diphenylamino group and a naphthylamino group.

In the general formula (1), “a linear or branched alkyl group having 1 to 20 carbon atoms having a substituent” represented by R ^{3 to} R ⁵ ;
"C3-C20 cycloalkyl group having a substituent",
"Alkoxy group having 1 to 20 carbon atoms having a substituent",
“A cycloalkoxy group having 3 to 20 carbon atoms having a substituent”,
“A linear or branched alkenyl group having 2 to 20 carbon atoms having a substituent”,
“Acyl group having 1 to 20 carbon atoms having a substituent”,
"Amino group having 0 to 20 carbon atoms having a substituent"
As the "substituent" in the "aromatic hydrocarbon group having 6 to 20 carbon atoms having a substituent" or the "heterocyclic group having 2 to 20 carbon atoms having a substituent",
As described above, “a linear or branched alkyl group having 1 to 20 carbon atoms having a substituent” represented by R ¹ and R ² in the general formula (1),
"C3-C20 cycloalkyl group having a substituent",
The same as the specific examples of the "substituent" in the "aromatic hydrocarbon group having 6 to 20 carbon atoms having a substituent" or "heterocyclic group having 2 to 20 carbon atoms having a substituent" Can be raised.

In the general formula (1), the combination of R ^{3 to} R ⁵ may be the same or different. R ³ and R ⁴ may be bonded to each other to form a ring, or may be a single bond or a bond formed through a nitrogen atom, an oxygen atom or a sulfur atom. Good. The ring formed in that case is preferably a 5-membered ring or a 6-membered ring.

In the general formula (1), R ^{3 to} R ⁵ are each a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an amino group, a carboxylic acid group, a sulfonic acid group, or a substituent having 1 to 1 carbon atoms. The acyl group of 5 is preferable, and a hydrogen atom, a halogen atom or a nitro group is more preferable.

The azo compound represented by the general formula (1) can be synthesized, for example, by the method shown in the following reaction formula (2). An azo compound such as the compound (A-1) exemplified below can be obtained by diazotizing p-trifluoromethylaniline by a conventional method and coupling it with a 3-aminophenol compound.

In the method of synthesizing the azo compound represented by the general formula (1), when the precipitated azo compound adheres strongly and interferes with stirring, an organic solvent may be mixed in order to eliminate or alleviate it. The organic solvent to be mixed is not particularly limited as long as the corresponding azo compound has sufficient solubility, and aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as n-hexane and n-heptane; acetone , 2-butanone, 2-pentanone, 3-pentanone, etc. ketones; ethyl acetate, butyl acetate, etc. esters; tetrahydrofuran (THF), dioxane, diethyl ether, etc. ethers; methanol, ethanol, propanol, isopropanol, butanol , Alcohols such as pentanol and pentanol; halogenated hydrocarbons such as dichloromethane and chloroform; N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP) and the like, alone or in combination. You can

The azo compound represented by the general formula (1) is obtained by purifying the product obtained by the above synthesis method by column chromatography, if necessary; adsorption purification by silica gel, activated carbon, activated clay, etc.; dispersion washing by a solvent. It can be obtained by performing known purification such as recrystallization, crystallization and salting out. The solvent used in these purification methods is not particularly limited, and alcohols such as water, methanol and ethanol; halogenated hydrocarbons such as dichloromethane and chloroform; aromatic hydrocarbons such as toluene and xylene; n-hexane and n. -Aliphatic hydrocarbons such as heptane may be used alone or in combination.

Specific examples of preferred compounds as the azo compound of the present invention represented by the general formula (1) are shown in the following formulas, but the present invention is not limited to these compounds. In the structural formulas below, some hydrogen atoms are omitted. In addition, even when stereoisomers exist, the plane structural formulas thereof are described.

The azo compound represented by the general formula (1) of the present invention may be used alone or in combination (for example, mixed) of two or more kinds having different molecular structures. In the weight concentration ratio, the weight concentration ratio of one azo compound having the smallest molecular structure is 0.1 to 50% by weight. That is, of the two or more azo compounds, the minimum amount of one azo compound accounts for 0.1 to 50% by weight of the total of the two or more azo compound dyes. The type of azo compound is preferably one or two.

The azo compound represented by the general formula (1) can also react with any metal to form a complex (or a complex compound). The azo compound in the present invention is expressed as an azo compound, including a complex compound composed of such an azo compound and a metal. The complex compound is obtained by reacting an azo compound represented by the general formula (1) with a positive metal ion “M” (for example, Patent Document 14). Positive metal ions represented by “M” include lithium ion, sodium ion, potassium ion, magnesium ion, calcium ion, cesium ion, barium ion, titanium ion, vanadium ion, chromium ion, manganese ion, iron ion, cobalt. Ion, nickel ion, copper ion, zinc ion, aluminum ion, zirconium ion, palladium ion, silver ion, tungsten ion, gold ion and the like, chromium ion, iron ion, cobalt ion, nickel ion, copper ion, zinc ion. , Aluminum ions are preferable, and nickel ions and zinc ions are particularly preferable.

Further, the positive metal ion represented by “M” of the present invention may be used alone or in combination of two or more. When two or more kinds of positive metal ions are combined and reacted with the azo compound to react, a mixture of the complex compounds is obtained.

The powder containing the azo compound of the present invention or the complex compound of an azo compound and a metal has a solvent molecule, water, a component of a molecular structure other than the azo compound of the present invention or a complex compound of the azo compound and a metal, and other components. May be included. Any of these may be used as it is, but those subjected to a purification treatment are preferable. However, a certain proportion of impurities may be present by any purification method, but it can be used if the purification is of the current state of the art.

Hereinafter, the azo compound or the coloring composition containing the azo compound (hereinafter, simply referred to as a coloring composition) represented by the general formula (1) of the present invention will be described in detail.

In order to enhance the performance of the coloring composition of the present invention as a colorant for a color filter, other components such as a surfactant, a dispersant, an antifoaming agent, a leveling agent, and other colorant for color filter during production are mixed. An organic compound such as an additive to be added can be added. However, the content of these additives in the coloring composition is preferably an appropriate amount, and the solubility of the coloring composition of the present invention in the solvent is lowered, or is improved more than necessary, and the color filter is also used. It is preferable that the content is in a range that does not affect the effects of other additives of the same type used during production. These additives can be added at any timing during the preparation of the coloring composition.

The powder form of the azo compound or the coloring composition of the present invention is usually used in the form of a solid powder having a crystal form, a microcrystal form, a fine powder form, a flake form, a needle crystal form, a granular form, or the like. However, it is not particularly limited.

The physical properties such as the powder state and particle size (particle size) of the azo compound or the coloring composition of the present invention can be obtained by known measurement methods such as particle size distribution, surface area, pore size distribution, powder density, and various microscope observations. The azo compound or the coloring composition of the present invention preferably has a particle size in the range of 0.1 μm to several mm, but the shape of the particles may change depending on the manufacturing conditions and the method of collecting the powder after drying, so that the specific shape of Although the particle size is not limited, a smaller particle size is preferred for high solubility, and a median particle size distribution in the range of 0.1 to 100 μm is preferred.

By performing thermogravimetric measurement-differential thermal analysis (TG-DTA) of the azo compound or the coloring composition of the present invention, the decomposition initiation temperature of these powders can be evaluated. Further, as the temperature corresponding to the decomposition start temperature, the temperature at the time point when a certain percentage (%) of weight is reduced after heating the sample may be used for evaluation. The decomposition initiation temperature is preferably 250° C. or higher, more preferably 300° C. or higher, and particularly preferably 360° C. or higher. When applied to a color filter, the higher the decomposition initiation temperature, the better.

The solubility of the powder of the azo compound or the coloring composition in the present invention is represented by the solubility, and the solubility is the maximum amount of the coloring composition in which the powdery compound or the coloring composition can be dissolved in a specific solvent. It represents a ratio, and is represented by a unit such as "weight %, (solvent name, temperature, etc.)". The solubility is obtained, for example, by mixing a sample with a specific solvent, stirring the solvent at a constant temperature for a constant time, and measuring the concentration of the prepared saturated solution. The solubility is measured by liquid chromatography (LC) or absorbance at the dissolution part. It can also be obtained by concentration measurement such as measurement.

The coloring composition contained in the colorant for the color filter needs to be well dissolved or dispersed in an organic solvent containing a resin in the manufacturing process of the colorant for the color filter and the color filter. Is preferably high. The organic solvent is not particularly limited, and specifically, esters such as ethyl acetate and n-butyl acetate; ethers such as diethyl ether and propylene glycol monomethyl ether (PGME); propylene glycol monomethyl ether acetate (PGMEA) ) And other ether esters; acetone, cyclohexanone and other ketones; methanol, ethanol and other alcohols; diacetone alcohol (DAA), etc.; benzene, toluene, xylene and other aromatic hydrocarbons; N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP) and other amides; dimethyl sulfoxide (DMSO) and the like. These solvents may be used alone or in combination of two or more. Among these, the azo compound or the coloring composition according to the present invention preferably has excellent solubility in PGMEA or PGMEA, and particularly preferably has excellent solubility in PGMEA.

The solubility of the powder of the azo compound or the coloring composition in the present invention is measured by gradually adding the powder until it remains dissolved in a certain amount of solvent, and is measured at around room temperature, that is, at 23 to 27° C., propylene glycol monomethyl ether acetate ( It was obtained by measuring the dissolved concentration in PGMEA).

The spectral characteristics (transmittance, reflectance) of the powder of the azo compound or the coloring composition of the present invention are as follows when the dye is used alone as the colorant for the color filter, or when it is used as a mixture with other dyes. Both are important and directly affect the color characteristics of the color filter. As a method of measuring the spectral characteristics, there is a method of measuring an absorption (or transmission) spectrum of a solution or a dispersion or a thin film prepared by coating on a glass or transparent resin substrate. Further, there is a method of directly irradiating the powder with light and measuring the light reflected/scattered on the particle surface or in the vicinity of the particle surface.

The colorant for a color filter of the present invention comprises an azo compound represented by the general formula (1) or a coloring composition containing the azo compound, and a component generally used for producing a color filter. In a general color filter, for example, in the case of a method using a photolithography process, a liquid prepared by mixing a dye such as a dye or a pigment with a resin component (including a monomer or an oligomer) or a solvent is used as a glass or a resin. It is obtained by coating on the substrate of No. 3, and photopolymerizing using a photomask to prepare a coloring pattern of a dye/resin composite film soluble/insoluble in a solvent, washing and heating. Also in the electrodeposition method and the printing method, a colored pattern is prepared by using a mixture of a dye and a resin or other components. Therefore, specific components of the colorant for a color filter of the present invention include azo compounds represented by the general formula (1), other dyes such as dyes and pigments, resin components, organic solvents, and photopolymerization initiators. And other additives. In addition, these components may be selected or omitted, and other components may be added if necessary.

When the coloring composition containing the azo compound of the present invention is used as a colorant for a color filter, it may be used in a color filter for each color, but it is preferably used as a colorant for a green or red color filter.

The colorant for a color filter containing the coloring composition containing the azo compound of the present invention may use the azo compound alone, or may be mixed with a known dye such as another dye or pigment for adjusting the color tone. You may. When used as a colorant for a red color filter, it is not particularly limited, but C.I. I. Pigment Red 177, C.I. I. Pigment Red 209, C.I. I. Pigment Red 242, C.I. I. Pigment Red 254 and the like; other red-based lake pigments; C.I. I. Acid Red 88, C.I. I. A red dye such as basic violet 10, C.I. I. Pigment Yellow 139, C.I. I. Pigment Yellow 83 and other yellow pigments. When used as a colorant for a blue color filter, although not particularly limited, C.I. I. Basic dyes such as Basic Blue 3, 7, 9, 54, 65, 75, 77, 99, 129; C.I. I. Acid dyes such as Acid Blue 9,74; Disperse dyes such as Disperse Blue 3, 7, 377; Spirone dyes: Cyanine type, indigo type, phthalocyanine type, anthraquinone type, methine type, triarylmethane type, indanthrene type , Oxazine-based, dioxazine-based, xanthene-based, azo-based not belonging to the present invention; other blue-based lake pigments, and other blue-based dyes or pigments. In the above dye, C.I. I. Means the color index.

The mixing ratio of the other dye in the colorant for a color filter containing the coloring composition containing the azo compound of the present invention is from 5 to 2000% by weight based on the azo compound (in the case of two or more kinds, the total thereof). It is preferably present, and more preferably 10 to 1000% by weight. The mixing ratio of dye components such as dyes in the liquid color filter colorant is preferably 0.5 to 70% by weight, and more preferably 1 to 50% by weight, based on the entire colorant.

The resin component in the color filter colorant containing the coloring composition containing the azo compound of the present invention may have a property necessary for a production method and a color filter resin film formed by using these. For example, a known material can be used. For example, acrylic resin, olefin resin, styrene resin, polyimide resin, urethane resin, polyester resin, epoxy resin, vinyl ether resin, phenol (novolac) resin, other transparent resins, photocurable resin or thermosetting resin, These monomers or oligomer components can be used in appropriate combination. Further, a copolymer of these resins may be used in combination. The content of the resin in these color filter colorants is preferably 5 to 95% by weight, and more preferably 10 to 50% by weight in the case of a liquid colorant.

Other additives in the color filter colorant containing the coloring composition containing the azo compound of the present invention include components necessary for polymerization and curing of a resin such as a photopolymerization initiator and a crosslinking agent, and Examples thereof include surfactants and dispersants necessary for stabilizing the properties of the components in the liquid color filter colorant. Any of these may be a known one for producing a color filter and is not particularly limited. The mixing ratio of the total amount of these additives in the total solid content of the color filter colorant is preferably 5 to 60% by weight, and more preferably 10 to 40% by weight.

The method and conditions for measuring the UV-visible transmission or absorption spectrum of the azo compound of the present invention will be specifically described below.
The measurement sample is preferably a sample prepared by using a propylene glycol monomethyl ether acetate (PGMEA) solvent so that the solution has a concentration of 0.02 mmol/L. The measurement wavelength range is preferably 300 to 750 nm. Further, the temperature to be measured is preferably 23 to 27°C.
The UV-visible transmission spectrum of the PGMEA solution of the azo compound of the present invention thus obtained has a low transmittance region showing an absorption maximum in the wavelength range of 350 to 500 nm,
It has a region having a high transmittance in the range of 750 nm or less from the longer wavelength side than the wavelength of 400 nm. In the comparatively narrow wavelength range between the low transmittance region and the high transmittance region, a steep portion of the spectrum is observed. An example of such an ultraviolet-visible transmission spectrum is shown in FIG. In FIG. 1, in the comparatively narrow wavelength range on the long wavelength side of 400 nm or more (in the vicinity of 500 nm in FIG. 1), such a steep slope of the UV-visible transmission spectrum has a low transmittance P and a point P. It is represented by the slope of a straight line (broken line) connecting the points Q with high transmittance.
Here, in the present invention, the magnitude of the slope of such an ultraviolet-visible transmission spectrum is
“Ratio of change amount (ΔT) of transmittance T (%) to change amount (Δλ) of wavelength λ (nm)”,
That is, “change rate of transmittance T” (ΔT(%)/Δλ(nm) or change rate ΔT/Δλ)
(Unit: transmittance%/nm). Regarding the range of the transmittance T for obtaining this value,
The lower transmittance is preferably 50% or less, and the higher transmittance is preferably 50% or more.
In the present invention, the rate of change of the transmittance T (ΔT(%)/Δλ(nm)) is
The rate of change of the transmittance T (ΔT(%)/Δλ(nm) within the range from the wavelength λ (nm) where the transmittance T is 30% to the wavelength λ (nm) where the transmittance T is 80% )) is preferred.
The value of this rate of change can be calculated by the following formula in the actual UV-visible transmission spectrum.
Change rate of transmittance T in UV-visible transmission spectrum=ΔT(%)/Δλ(nm)
={80(%)-30(%)}/{wavelength (nm) with a transmittance of 80%-wavelength (nm) with a transmittance of 30%}
Where, for example,
In the case of “within the range from the wavelength λ (nm) where the transmittance T is 30% to the wavelength λ (nm) where the transmittance T is 80%”, ΔT=50 nm.
At that time, when the wavelength range Δλ where the transmittance changes sharply, represented by {wavelength (nm) at 80% transmittance−wavelength (nm) at 30% transmittance) is 50 nm,
Change rate of transmittance T ΔT (%)/Δλ (nm)=1 (transmittance %/nm)
Next to
Further, in the case of Δλ=25 nm with a narrow wavelength range,
ΔT(%)/Δλ(nm)=2 (transmittance%/nm), and it can be seen that the steeper the slope of the spectrum, the greater the rate of change of the transmittance T.
In the azo compound of the present invention, the value of the change rate is preferably 2 (transmittance%/nm) or more.

Hereinafter, the embodiments of the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples. The compounds obtained in the examples were identified by ¹ H-NMR analysis (JEOL Ltd. nuclear magnetic resonance apparatus, JNM-ECA-600).

The UV-visible transmission spectrum of the azo compound of the present invention was prepared by using a PGMEA solvent to prepare a measurement sample as a solution having a concentration of 0.02 mmol/L, and using a V-650 UV-visible spectrophotometer manufactured by JASCO Corporation. Then, the UV-visible transmission spectrum or absorption spectrum from 300 nm to 750 nm was measured by a conventional method. From the measurement results, the maximum absorption wavelength, the transmittance values of 80% and 30% were read.

[Synthesis Example 1] Synthesis of compound (A-1) Using 50 mL Kolben, p-trifluoromethylaniline (2.00 g, 12.4 mmol) and concentrated hydrochloric acid (7.0 mL, 79.3 mmol) were added to an aqueous solution of sodium nitrite. 7 mL of an aqueous solution of was added in an ice bath, the mixture was stirred for 2 hours, and then sulfamic acid (120 mg) was added. This solution was added to 100 mL of an aqueous solution of 2.75 g (12.4 mmol) of 3-dibutylaminophenol and 2.68 g (67.0 mmol) of sodium hydroxide in an ice bath. After stirring at room temperature (25° C.) for about 3 hours, the resulting solid was collected by suction filtration. 4.71 g of the obtained crude product was purified by silica gel column chromatography (silica gel 120 g, n-hexane/ethyl acetate=10:1) to give compound (A-1) (yield: 2.09 g, yield: 43%).

[Example 1]
A PGMEA solution having a concentration of 0.02 mmol/L of the compound (A-1) obtained in Synthesis Example 1 was prepared, and the UV-visible spectrum at room temperature (25°C) was measured. From the measurement results, the values of wavelengths with a transmittance of 80% and 30% were read. The rate of change ΔT(%)/Δλ(nm) from the transmittance of 30% to 80% (unit: transmittance%/nm) was calculated by the following mathematical expression using the read value. Next, the solubility (PGMEA, 25°C) in the PGMEA solvent at room temperature (25°C) was measured. The results of these measurements are shown in Table 1.

[Comparative Example 1]
For comparison, the compound (A-1) of Example 1 is used as a dye which does not belong to the present invention and does not have a hydroxyl group at a specific position in the dye molecule like the following compound (B-1). The same measurement as in the example was performed except that the dye was changed. The results are shown in Table 1.

As shown in Table 1, the compounds of Examples, which are azo compounds of the present invention, have a larger rate of change in transmittance T and a sharp slope of rising spectrum than the compounds of the dyes of Comparative Examples. I understood it. Further, the solubility of the azo compound of the present invention in PGMEA is comparable to that of the dye of Comparative Example.

The azo compound according to the present invention is useful as a color filter dye excellent in color developability and solubility, and a coloring composition containing the compound is suitable as a color filter colorant. Further, by using the colorant, a color filter having excellent color developability (color gamut, brightness, contrast ratio, etc.) can be obtained.

Claims (8)

An azo compound represented by the following general formula (1).

[Wherein R ¹ and R ² are each independently
A linear or branched alkyl group having 1 to 20 carbon atoms, which may have a substituent,
A cycloalkyl group having 3 to 20 carbon atoms, which may have a substituent,
Represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent, or a heterocyclic group having 2 to 20 carbon atoms which may have a substituent,
They may be bonded to each other to form a ring.
R ^{3 to} R ⁵ are each independently
Hydrogen atom, halogen atom, hydroxyl group, nitro group, cyano group, carboxylic acid group, sulfonic acid group,
A linear or branched alkyl group having 1 to 20 carbon atoms, which may have a substituent,
A cycloalkyl group having 3 to 20 carbon atoms, which may have a substituent,
A linear or branched alkoxy group having 1 to 20 carbon atoms, which may have a substituent,
A cycloalkoxy group having 3 to 20 carbon atoms which may have a substituent, a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent,
An acyl group having 1 to 20 carbon atoms which may have a substituent,
An amino group having 0 to 20 carbon atoms, which may have a substituent,
Represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent, or a heterocyclic group having 2 to 20 carbon atoms which may have a substituent,
R ³ and R ⁴ may combine with each other to form a ring. ] The azo according to claim 1, wherein in the general formula (1), R ¹ and R ² are linear or branched alkyl groups having 3 to 10 carbon atoms which may have a substituent. Compound. In the general formula (1), R ^{3 to} R ⁵ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an amino group, a carboxylic acid group or a sulfonic acid group,
The azo compound according to claim 1 or 2. In the ultraviolet-visible transmission spectrum (wavelength side of 400 nm or longer) measured at 23 to 27° C. using a propylene glycol monomethyl ether acetate (PGMEA) solution having a concentration of the azo compound of 0.02 mmol/L,
Ratio of change amount (ΔT) of transmittance to change amount (Δλ) of wavelength in the range from wavelength λ (nm) where transmittance T is 30% to wavelength λ (nm) where transmittance T is 80% (Change rate of transmittance T)
(ΔT(%)/Δλ(nm)) is 2 (transmittance%/nm) or more,
The azo compound according to any one of claims 1 to 3. The azo compound according to any one of claims 1 to 4, wherein the solubility of the azo compound in propylene glycol monomethyl ether acetate (PGMEA) at 23 to 27°C is 3% by weight or more. A coloring composition containing the azo compound according to any one of claims 1 to 5. A colorant for a color filter, comprising the coloring composition according to claim 6. A color filter using the colorant for a color filter according to claim 7.

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