JP6737111B2 - Quinophthalone compound, ink containing quinophthalone compound, and display containing the ink - Google Patents

Description

The present invention relates to a quinophthalone compound and an ink containing a quinophthalone compound, and more particularly to a quinophthalone compound having a specific chemical structure and an ink containing the compound and useful as a display material or an optical shutter.

An electrowetting display (hereinafter, referred to as EWD) has a plurality of pixels filled with two phases of an aqueous medium and an oil-based colored ink on a substrate, and an on-off of voltage application for each pixel causes an aqueous medium/oil-based display. This is an image display format in which the affinity of the interface of the colored ink is controlled and the oily colored ink is spread/aggregated on the substrate (Non-Patent Document 1). The dye compound contained in the ink used for EWD is required to have high solubility in a low polar solvent and light resistance (Patent Document 1).

In Patent Document 1, an azo dye compound, which is widely known as a thermal transfer recording material, is modified to be a dye compound for an EWD ink.
On the other hand, as thermal transfer recording materials, in addition to azo dye compounds, many dye compounds such as quinophthalone dye compounds (Patent Document 2) are known.

International Publication No. 2009/063880 Japanese Patent Laid-Open No. 06-145540

"Nature", (UK), 2003, Vol. 425, p. 383-385

However, according to a study by the present inventors, the dye compound used in the EWD ink described in Patent Document 1 is still insufficient in light resistance, and the dye compound described in Patent Document 2 is a low polar solvent. It has been found that the solubility in the is low and it is difficult to apply as it is.
In view of the above circumstances, an object of the present invention is to provide a new dye compound for EWD, which has good light resistance and high solubility in a solvent.

The present inventors have found a compound having both high solubility and good light resistance by improving a quinophthalone-based coloring compound as a coloring compound for an EWD ink, and completed the present invention.
That is, the gist of the present invention is as follows.
(1) A solvent having a relative dielectric constant of 3 or less at 22° C. at a measurement frequency of 1 kHz and a solubility of 20 mg/L or less in water at 25° C., and a quinophthalone compound represented by the following general formula (1): Ink containing.

(In the formula, R ^{1 to} R ⁶ each independently represent a hydrogen atom, an alkyl group which may have a substituent, a halogen group, an alkylthio group, an alkyloxy group, an alkylamino group or a hydroxyl group. ^At least one of ^{1 to} R ⁶ represents a hydroxyl group, and R ^{7 to} R ¹⁰ each independently represent a hydrogen atom, an alkyl group which may have a substituent, a COOR ¹¹ group, a CONR ¹² R ¹³ group, A SO ₂ R ¹⁴ group or a SO ₂ NR ¹⁵ R ¹⁶ group is represented, and R ^{11 to} R ¹⁶ represent a linear or branched alkyl group which may have a substituent.)

(2) R ^{1 to} R ⁶ are each independently a hydrogen atom, an alkyl group which may have a substituent, a halogen group or a hydroxyl group, and R ^{11 to} R ^{16 each} have a substituent. The ink according to (1), which represents an optionally branched alkyl group.
(3) The ink according to (1), wherein any of R ^{1 to} R ⁶ is an alkylthio group, an alkyloxy group or an alkylamino group.
(4) The ink according to (3), wherein R ² is an alkylthio group, and the alkyl portion of the alkylthio group is a branched alkyl having 4 or more carbon atoms which may have a substituent.

(5) The ink according to any one of (1) to (4), wherein at least one of R ^{7 to} R ¹⁰ is a COOR ¹¹ group or a CONR ¹² R ¹³ group.
(6) The ink according to any one of (1) to (5), wherein the halogen group is a bromine atom.
(7) The ink according to any one of (1) to (6), wherein R ^{11 to} R ¹⁶ are branched alkyl groups each having 4 or more carbon atoms and may have a substituent.
(8) An electrowetting display containing the ink according to any one of (1) to (7).
(9) A quinophthalone compound represented by the following general formula (1).

(In the formula, R ^{1 to} R ⁶ each independently represent a hydrogen atom, an alkyl group which may have an arbitrary substituent, a halogen group or a hydroxyl group, and at least one of R ^{1 to} R ⁶ Represents a hydroxyl group, and R ^{7 to} R ¹⁰ each independently represent a hydrogen atom, an alkyl group having an arbitrary substituent, a COOR ¹¹ group, a CONR ¹² R ¹³ group, a SO ₂ R ¹⁴ group, or a SO ₂ NR ¹⁵ R ¹⁶ Group, at least one of R ^{7 to} R ¹⁰ is a COOR ¹¹ group or CONR.
¹² R ¹³ group, and R ^{11 to} R ¹⁶ each represent a linear or branched alkyl group which may have a substituent. )

(10) The R ^{1 to} R ⁶ are each independently a hydrogen atom, an alkyl group which may have a substituent, a halogen group or a hydroxyl group, and the R ^{11 to} R ^{16 each} have a substituent. The quinophthalone-based compound according to (9), which may represent a branched alkyl group having 4 or more carbon atoms.
(11) The quinophthalone compound according to (9), wherein any of R ^{1 to} R ⁶ is an alkylthio group, an alkyloxy group or an alkylamino group.
(12) The quinophthalone-based compound according to (11), wherein R ² is an alkylthio group, and the alkyl part of the alkylthio group is a branched alkyl having 4 or more carbon atoms which may have a substituent. ..
(13) The quinophthalone compound according to any one of (9) to (12), wherein the halogen group is a bromine atom.

The quinophthalone-based compound of the present invention and the ink containing the quinophthalone-based compound have high solubility particularly in a low-polarity solvent and excellent light resistance, and thus are useful for inks used for displays and optical shutters. is there. The display has a display portion containing ink and displays an image by controlling voltage application to the display portion, a display which displays an image by changing a coloring state by voltage application, and an electrophoretic display portion. It is particularly useful for displays and EWDs that display using particles or aqueous media.

Hereinafter, the embodiments of the present invention will be specifically described, but the present invention is not limited to the following embodiments and can be variously modified and implemented within the scope of the gist thereof.
The ink of the present invention has a relative dielectric constant of 3.0 or less measured at a frequency of 1 kHz and a temperature of 22° C., and a solubility in water at 25° C. of 20 mg/L or less, and the following general formula (1). Is an ink containing a quinophthalone compound represented by.

In the formula (1), R ^{1 to} R ⁶ each independently represent a hydrogen atom, an alkyl group which may have a substituent, a halogen group or a hydroxyl group, and at least 1 of R ^{1 to} R ⁶ is present. Represents a hydroxyl group, and R ^{7 to} R ¹⁰ each independently represent a hydrogen atom, an alkyl group which may have a substituent, a COOR ¹¹ group, a CONR ¹² R ¹³ group, a SO ₂ R ¹⁴ group or a SO ₂ group. represents NR ¹⁵ R ^{16 radical,} R 11 ^{to R 16} represent may have a substituent group linear or branched alkyl group.

(solvent)
A display or an optical shutter to which the ink of the present invention is applied uses a low-polarity solvent as the ink solvent. The ink of the present invention has layers such as an aqueous layer and an oil layer, and the layers are separated (br
It can be used for display devices based on eak up) or move aside. In order to make the display clear, it is necessary that the oil layer containing the ink does not mix with the water layer and stably splits or moves, so the solvent has a low compatibility with water and a low polarity. Something is required. In the present invention, the inclusion of a specific solvent and an azo compound in the ink enables the oil layer to stably split or move.

Further, in a device for displaying using electrophoretic particles in a solvent, driving may be hindered if the dielectric constant of the solution is large. By using the specific solvent and azo compound of the present invention, it is possible to color the solution without hindering the movement of particles.
The solvent used in the present invention has a relative dielectric constant of 3.0 or less measured at a frequency of 1 KHz and 22°C. It is preferably 2.5 or less, more preferably 2.2 or less. Although the lower limit of the relative dielectric constant is not particularly limited, it is usually 1.5 or more, preferably 1.8 or more. The relative dielectric constant of the solvent is measured by the method described in the examples. When a plurality of solvents are mixed and used as a solvent for the ink, the relative dielectric constant refers to the relative dielectric constant of the entire mixed solvent.

When the relative permittivity of the layer containing ink is in the above range, the display device tends to be driven without trouble. For example, when the other layer containing no ink is water, a liquid such as a salt solution having electrical conductivity or polarity, the relative dielectric constant of the solvent used for the layer containing ink is within the above range, The layers tend not to mix.
The method for measuring the relative dielectric constant of the solvent in the present invention is shown below.

It is measured by an impedance meter method using an LCR meter. The solvent is sandwiched between parallel plate glass substrates with ITO electrodes facing each other with an electrode interval of 30 μm, and then the test signal voltage of 0.1 V is applied at room temperature (25° C.) and measurement frequency (1 kHz). The capacitance is measured and the relative permittivity is determined by the calculation by the following formula.
Relative permittivity = equivalent parallel capacitance x electrode spacing/electrode area/vacuum permittivity (ε0)
The solvent used in the present invention has a solubility in water at 25° C. of 20 mg/L or less. It is preferably 10 mg/L or less, more preferably 5 mg/L or less. When the solubility in water is equal to or less than the above specific value, for example, the oil layer does not mix with the water layer and the display device tends to be driven without trouble.

The method of measuring the solubility of the solvent according to the present invention in water is as follows.
30 g of pure water and 8 g of solvent are put in a 110 ml vial and shaken in a thermostat at 25° C. at 200 times/min for 4 hours. The liquid after shaking is centrifuged (6000×g, 5 minutes), the aqueous layer is sampled, and the concentration of the dissolved solvent is quantified by gas chromatography.
When the solvent species used is unknown, the solubility in water can be measured by the above method by identifying the solvent species by mass spectrometry or the like. When a plurality of solvents are mixed and used as a solvent, the solubility in water refers to the solubility of the whole mixed solvent.

When a plurality of solvents are mixed and used as a solvent for the ink, the solubility in water refers to the solubility of the entire mixed solvent.
The boiling point of the solvent of the present invention is not particularly limited, but is preferably 120°C or higher, more preferably 150°C or higher, and particularly preferably 170°C or higher. Further, it is preferably 300° C. or lower. When the boiling point is not too high, the melting point and viscosity of the solvent do not become too high, and the driving tends to be smooth when used in a display device. Further, since the boiling point is not too low, it tends to be less likely to volatilize, and stability and safety tend to be obtained.

The viscosity of the solvent used in the present invention is not particularly limited, but the viscosity at a solvent temperature of 25° C. is preferably 0.1 mPa·s or more. Further, it is preferably 10000 mPa·s or less, more preferably 1000 mPa·s or less, and particularly preferably 100 mPa·s or less. When the viscosity of the solvent is not too large, the compound and the like are likely to be dissolved, and further, the driving tends to be smooth when used in a display device.

The solvents can be used alone or in combination. Specific examples include hydrocarbon solvents, fluorocarbon solvents, fluorine-based inert liquids, silicone oils and the like.
Examples of the hydrocarbon solvent include linear or branched aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, aromatic hydrocarbon solvents and petroleum naphtha.
Examples of the aliphatic hydrocarbon solvent include n-decane, isodecane, decalin, nonane, dodecane, isododecane, tetradecane, hexadecane, isoalkanes and the like.

Examples of the alicyclic hydrocarbon solvent include Isopar E, Isopar G, Isopar H, Isopar L, Isopar M (registered trademark, manufactured by Exxon Mobil Corporation), IP Solvent (registered trademark, manufactured by Idemitsu Petrochemical Co., Ltd.). ), Soltor (manufactured by Philips Oil Co., Ltd.) and the like.
Examples of the aromatic hydrocarbon solvent include alkylnaphthalene and tetralin.

Examples of the petroleum naphtha-based solvent include Shell S.I. B. R. , Shellsol 70, Shellsol 71 (manufactured by Shell Petrochemical Co., Ltd.), Pegasol (manufactured by Exxon Mobil), and Hisosol (manufactured by Nippon Oil Co., Ltd.). The fluorocarbon-based solvent, a predominantly fluorine-substituted hydrocarbon, _e.g., perfluoroalkanes are exemplified represented by _C n _{F 2n + 2,} such as _{C 7 F 16, C 8 F} 18. Examples of commercially available products include Fluorinert PF5080 and Fluorinert PF5070 (manufactured by Sumitomo 3M Ltd.).

As the fluorine-based inert liquid, for example, Fluorinert FC series (manufactured by Sumitomo 3M), etc., as the fluorocarbon, for example, Krytox GPL series (registered trademark, manufactured by DuPont Japan Limited), and as CFCs, for example, HCFC-141b (manufactured by Daikin Industries, _Ltd.), as _{F (CF 2) 4 CH 2} CH 2 I, F (CF 2) iodinated fluorocarbons such as ₆ I, for example, I-1420, I-1600 ( Daikin Fine Chemical Laboratory) and the like.

Examples of the silicone oil include low-viscosity synthetic dimethylpolysiloxane, and examples of commercially available products include KF96L (manufactured by Shin-Etsu Silicone) and SH200 (manufactured by Toray Dow Corning Silicone).
Among these solvents, in the use of the display to which the present invention is applied, an aliphatic hydrocarbon solvent is preferable from the viewpoint of preventing mixing with an aqueous layer, more preferably tetradecane, decalin or n-decane, and particularly preferably Is n-decane.

Further, a mixed solvent containing a solvent of a different type from the above-mentioned solvent may be used, but in that case, it is preferable to contain at least one selected from the group consisting of a hydrocarbon solvent, a fluorocarbon solvent and a silicone oil. The content of the preferable solvent is usually 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more based on the whole solvent.

When a mixed solvent is used in the present invention, it is considered that the interaction between the solvents is relatively small, and the relative permittivity of the mixed solvent is the relative permittivity of each solvent constituting the mixed solvent obtained by dividing each volume fraction by It is approximated by the value obtained by multiplying. Similarly, the solubility of the mixed solvent in water is approximated by a value obtained by multiplying the solubility of each solvent constituting the mixed solvent in water by the respective mole fractions and summing up.

The ink of the present invention contains the above-mentioned specific solvent and a quinophthalone-based compound, and is obtained by dissolving the quinophthalone-based compound and other compounds and additives used as necessary in a solvent.
Here, the term "dissolution" means that the quinophthalone compound does not have to be completely dissolved in the solvent, but the quinophthalone compound can pass through a filter having a size of about 0.1 micron and the extinction coefficient can be measured. The fine particles of the compound may be dispersed.

(The quinophthalone compound represented by the general formula (1))
The quinophthalone compound having the structure represented by the general formula (1) of the present invention will be described below.

(In the formula, R ^{1 to} R ⁶ each independently represent a hydrogen atom, an alkyl group which may have a substituent, a halogen group, an alkylthio group, an alkyloxy group, an alkylamino group or a hydroxyl group. ^At least one of ^{1 to} R ⁶ represents a hydroxyl group, and R ^{7 to} R ¹⁰ each independently represent a hydrogen atom, an alkyl group which may have a substituent, a COOR ¹¹ group, a CONR ¹² R ¹³ group, A SO ₂ R ¹⁴ group or a SO ₂ NR ¹⁵ R ¹⁶ group is represented, and R ^{11 to} R ¹⁶ represent a linear or branched alkyl group which may have a substituent.)

<R ^{1 to} R ⁶ >
R ^{1 to} R ⁶ each independently represent a hydrogen atom, an alkyl group which may have a substituent, a halogen group, an alkylthio group, an alkyloxy group, an alkylamino group or a hydroxyl group, and R ^{1 to} R ⁶ At least one of these represents a hydroxyl group. Further, any of R ^{1 to} R ⁶ is preferably an alkylthio group, an alkyloxy group or an alkylamino group. By using these substituents, decomposition due to light is suppressed, and thus the effect of improving light resistance can be seen.

The alkyl group which may have a substituent of R ^{1 to} R ⁶ may be linear or branched, and may be a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group. , I-butyl group, t-butyl group, isopentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group and the like. Among them, the total carbon number including the substituents is preferably 1-8, and more preferably 1-6. This is because the solubility in the solvent used in the present invention can be improved.

As the substituent, a halogen group, an alkoxy group, an aryl group, a cyano group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acylamino group, a dialkylamino group, an alkylarylamino group, a diarylamino group, an alkyl group. Examples thereof include a sulfonylamide group, an arylsulfonylamide group, a trialkylsilyl group, a trialkoxysilyl group and a thioalkyl group.

The alkyl group of R ^{1 to} R ⁶ may be linear or branched and may be a methyl group, an ethyl group, an n-propyl group, an n-butyl group, or an n-butyl group. -Pentyl group, n-hexyl group, n-heptyl group, n-octyl group, i-propyl group, i-butyl group, t-butyl group, 2-ethylbutyl group, isopentyl group, 2-methylpentyl group, 3- Methylpentyl group, 4-methylpentyl group, 2-ethylhexyl group, 2,2-dimethylhexyl group, 2-methylheptane group, 2-butyloctyl group, 2-hexyloctyl group, 2-methylhexadecyl group, 2- Hexyldecyl group, 2-n-octyldodecyl group, 2-hexyldecyl group, 2-heptylundecyl group, 2-methylhexadecyl group, 2-hexadecyloctadecyl group, 2-methylcyclohexyl group, 1-cyclohexyl-1 A butyl group and the like. Above all, the total carbon number including the substituent portion is preferably 30 or less, more preferably 25 or less, and most preferably 20 or less. This makes it possible to provide a compound having an appropriate solubility.

Further, these alkyl groups may have a substituent, and as the substituent, a halogen group, an alkoxy group, an aryl group, a cyano group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, Examples thereof include an acylamino group, a dialkylamino group, an alkylarylamino group, a diarylamino group, an alkylsulfonylamide group, an arylsulfonylamide group, a trialkylsilyl group, a trialkoxysilyl group and a thioalkyl group.

Examples of the halogen group of R ^{1 to} R ⁶ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Most preferred is a bromine atom. This is because the spectral shape of the absorption wavelength can be made steeper.
At least one of R ^{1 to} R ⁶ is a hydroxyl group. This is because the hydroxyl group and the ketone group contained in the molecular structure form a hydrogen bond to improve the light resistance of the compound alone or in the solution. The number of hydroxyl group substitutions is more preferably 4 or less, further preferably 2 or less, and most preferably 1.

Particularly, R ² is preferably a hydrogen atom, an alkyl group which may have a substituent, a halogen group, an alkylthio group, an alkyloxy group or an alkylamino group, more preferably a hydrogen atom, a halogen group or an alkylthio group. Group, an alkyloxy group or an alkylamino group, more preferably a hydrogen atom, a halogen group or an alkylthio group, and most preferably a halogen group or an alkylthio group. These tend to suppress photodecomposition and improve light resistance.
Further, it is preferable that R ² is an alkylthio group, and the alkyl portion of the alkylthio group is a branched alkyl having 4 or more carbon atoms which may have a substituent.

<<Combination of R ^{1 to} R ⁶ >>
As a combination of R ^{1 to} R ^6, the combinations as shown in Table 1 and Table 2 can be considered. Among these, Entry 1-01, 1-02, 1-04, 1-05, 1-09, 1-17, 1-18, 1-20, 1-21, 1-25, 1-33, 1-34. , 1-36, 1-37, 1-41, 1-49, 1-50, 1-51, 1-57, 1-58, 1-59, 1-65, 1-66, 1-67 are preferable. , Entry1-01, 1-05, 1-17, 1-21, 1-33, 1-37, 1-49, 1-51, 1-59, 1-65, 1-67 are more preferable. This makes it possible to achieve both good light resistance and good solubility.

<R ^{7 to} R ¹⁰ >
R ^{7 to} R ¹⁰ each independently represent a hydrogen atom, an alkyl group which may have a substituent, a COOR ¹¹ group, a CONR ¹² R ¹³ group, a SO ₂ R ¹⁴ group or a SO ₂ NR ¹⁵ R ¹⁶ group. , R ^{11 to} R ¹⁶ each represent a linear or branched alkyl group which may have a substituent.
Further, any one of R ^{7 to} R ¹⁰ is preferably a COOR ¹¹ group, a CONR ¹² R ¹³ group, a SO ₂ R ¹⁴ group or a SO ₂ NR ¹⁵ R ¹⁶ group, and more preferably COOR ^{11 group.} Or a CONR ¹² R ¹³ group. This is because the electronic state of the molecule can be appropriately controlled, and the maximum absorption wavelength can be appropriately adjusted.

The alkyl group which may have a substituent of R ^{7 to} R ¹⁰ may be linear or branched, and may be a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group. , I-butyl group, t-butyl group, isopentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group and the like. The alkyl group is preferably unsubstituted. When it has a substituent, examples of the substituent include a halogen group, an alkoxy group, an aryl group, a cyano group, an aryloxy group, an alkoxycarbonyl group, and an aryloxycarbonyl group. Among them, those having 1 to 8 carbon atoms are preferable, those having 1 to 6 carbon atoms are more preferable, and alkyl groups having 1 to 4 carbon atoms are more preferable.

<<R ^{11 to} R ¹⁶ >>
R ^{11 to} R ¹⁶ represent a linear or branched alkyl group which may have a substituent, and a branched alkyl group is more preferable. The upper limit of the carbon number of the linear alkyl group is preferably 30 or less, more preferably 20 or less, further preferably 15 or less, and most preferably 12 or less. This makes it possible to have good light resistance. The upper limit of the carbon number of the branched alkyl is preferably 30 or less, more preferably 20 or less, still more preferably 15 or less. The lower limit of the number of carbon atoms is preferably 2 or more, more preferably 3 or more, still more preferably 4 or more, and most preferably 6 or more. This makes it possible to have good solubility.

Moreover, when said R< ¹ >-R< ⁶ > is a hydrogen atom, the alkyl group which may have a substituent, a halogen group, or a hydroxyl group each independently, that is, said R< ¹ >-R< ⁶ > is an alkylthio group, alkyl. When neither an oxy group nor an alkylamino group is contained, R ^{11 to} R ¹⁶ are preferably branched alkyl groups which may have a substituent, and more preferably have 4 or more carbon atoms. .. As a result, the affinity with the solvent is improved, so that it is possible to have an appropriate solubility.

Examples of the branched alkyl group include i-propyl group, i-butyl group, t-butyl group, 2-ethylbutyl group, isopentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 2 -Ethylhexyl group, 2,2-dimethylhexyl group, 2-methylheptane group, 2-butyloctyl group, 2-hexyloctyl group, 2-methylhexadecyl group, 2-hexyldecyl group, 2-n-octyldodecyl group , 2-hexyldecyl group, 2-heptylundecyl group, 2-methylhexadecyl group, 2-hexadecyloctadecyl group, 2-methylcyclohexyl group, 1-cyclohexyl-1-butyl group. More preferably, 2-ethylhexyl group, 2,2-dimethylhexyl group, 2-methylheptane group, 2-butyloctyl group, 2-hexyloctyl group, 2-methylhexadecyl group, 2-hexyldecyl group, 2- n-octyldodecyl group, 2-hexyldecyl group, 2-heptylundecyl group, 2-methylhexadecyl group, and more preferably 2-ethylhexyl group, 2-hexyloctyl group from the viewpoint of improving solubility. Group, 2-hexyldecyl group, and 2-n-octyldodecyl group. Among them, the total number of carbon atoms including the substituent is preferably 1 to 8, and more preferably 1 to 6 carbon atoms. This is because the solubility in the solvent used in the present invention can be improved.

Examples of the linear alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, Examples thereof include n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group and n-icosyl group.
The substituent which the above linear or branched alkyl group may have, is a halogen group, an alkoxy group, an aryl group, a cyano group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acylamino group, Examples thereof include a dialkylamino group, an alkylarylamino group, a diarylamino group, an alkylsulfonylamide group, an arylsulfonylamide group, a trialkylsilyl group, a trialkoxysilyl group and a thioalkyl group.

<Combination of R ^{1 to} R ⁶ and R ^{7 to} R ¹⁰ >
As the combinations of R ^{1 to} R ⁶ and R ^{7 to} R ¹⁰ described above, the combinations shown in Table 3 below can be considered. Of these, Entry 2-01, 2-02, 2-07, 2-08, 2-11, 2-12, 2-17, 2-18, 2-21, 2-22, 2-27, 2-28. , 2-31, 2-32, 2-37, 2-38, 2-41, 2-42, 2-43, 2-44 are preferable, and Entry 2-07, 2-08, 2-11, 2-12. , 2-17, 2-18, 2-21, 2-22, 2-27, 2-28, 2-31, 2-32, 2-41, 2-42, 2-43, 2-44 are more preferable. preferable. This makes it possible to achieve both good light resistance and good solubility. The numbers shown in R ^{1 to} R ⁶ correspond to the Entry in Tables 1 and 2 described above.

<Molecular weight>
When the quinophthalone compound of the present invention has a substituent, the molecular weight of the compound including the substituent is preferably 1500 or less, more preferably 1000 or less. It is usually 400 or more. When the molecular weight is in the above range, a good Gram extinction coefficient can be obtained.

<Specific examples of the quinophthalone compound represented by the general formula (1)>
Specific examples of the quinophthalone compound represented by the general formula (1) include the following compounds.

<Method for synthesizing quinophthalone compound represented by general formula (1)>
The method for producing the quinophthalone compound of the present invention is not particularly limited, and conventionally known methods can be appropriately used. Hereinafter, an embodiment of a method for producing a quinophthalone compound will be described.
First, as shown by the following chemical formula, a quinophthalone derivative can be synthesized by reacting a 2-methylquinoline derivative and a phthalic anhydride derivative.

When halogen or the like is introduced onto the quinoline skeleton, it can be introduced onto the quinoline skeleton in advance. It is also possible to introduce the quinophthalone derivative after the synthesis by using a halogenating reagent such as iodine, bromine, chlorine or N-bromosuccinimide.
When the quinophthalone derivative has a carboxylic acid group, a compound having an ester group or an amide group can be synthesized by reacting a desired alcohol derivative or amine derivative. Examples of this method include a condensation reaction with an acid catalyst. Alternatively, the carboxylic acid contained in the quinophthalone derivative may be converted to an acid halide with thionyl chloride or the like, and then reacted with an alcohol derivative or an amine derivative.

<Solubility of quinophthalone compound represented by general formula (1)>
The quinophthalone compound of the present invention has a solubility in a solvent, particularly a solvent having a relative dielectric constant of 3.0 or less measured at a frequency of 1 KHz and 22° C. and a water solubility of 20 mg/L or less at 25° C. It is characterized by excellent.
The quinophthalone compound of the present invention has a solubility in n-decane at 5°C of usually 0.1% by mass or more, preferably 0.5% by mass or more, and more preferably 1.0% by mass or more. The higher the solubility, the more preferable, but it is usually about 80% by mass or less. When the solubility is equal to or higher than the specific value, it may be possible to display on a display device such as a display.

The solubility of the quinophthalone compound of the present invention in n-decane can be measured by the method described in Examples below.
The quinophthalone compound of the present invention is preferably water-insoluble in principle when used for EWD. The "water-insoluble" in the present invention means that the solubility in water under the condition of 25°C and 1 atm is 0.1% by mass or less, preferably 0.01% by mass or less.

Further, it is preferred that the molar extinction coefficient is ^{10000 (L · mol -1 · cm} -1) or more, preferably ^{15000 (L · mol -1 · cm} -1) or more, 20000 (L · mol ^- It is particularly preferable that it is ¹ ·cm ⁻¹ ) or more in order to satisfy the performance of the display device.
Furthermore, the molar absorption coefficient ε (L·mol ⁻¹ ·cm ⁻¹ ) of the quinophthalone compound of the present invention at the absorption maximum wavelength in the n-decane solution and the saturation concentration of the quinophthalone compound at 5° C. with respect to n-decane. The value of the product εC with C(mol·L ⁻¹ ) is preferably 100 cm ⁻¹ or more, more preferably 200 cm ⁻¹ or more, more preferably 400 cm ⁻¹ or more. The higher the εC value is, the higher the coloring property is, which is preferable, and there is no particular upper limit, but it is usually 100,000 cm ⁻¹ or less.

(Regarding the composition of the ink of the present invention)
The concentration of the quinophthalone compound in the ink of the present invention may be adjusted to any concentration depending on its purpose. For example, when it is used as a dye for an EWD ink, it is usually used at a concentration of 1% by mass or more and diluted with a solvent according to the required concentration, but preferably 3% by mass or more, more preferably 5% by mass. That is all. Further, it is usually preferably about 80% by mass or less.

The ink of the present invention may contain the above quinophthalone compound alone, or may contain two or more kinds containing other compounds in any combination and ratio.
INDUSTRIAL APPLICABILITY The quinophthalone compound of the present invention is excellent in solubility in a solvent and has a high extinction coefficient, and therefore, it is useful as a material for optical shutters, a display material, particularly an electrowetting display material, an electrophoretic display material.

The ink viscosity of the present invention when the ink temperature is 25° C. is usually preferably 0.1 mPa·s or more. Further, it is preferably 10000 mPa·s or less, more preferably 1000 mPa·s or less, and particularly preferably 100 mPa·s or less. If the viscosity of the ink is too large, the driving of the display device may be hindered.
Regarding the relative dielectric constant and viscosity of the solvent according to the present invention and the ink containing the solvent and the dye, the smaller the difference between the values of the solvent and the ink, the smaller the influence on the driving characteristics when used in a display device or the like. preferable. Therefore, the ink of the present invention may contain any additive suitable for each application, if necessary, within a range that does not impair the effects of the present invention, but does not significantly change the properties of the solvent. Preferably.

(Regarding other compounds that may be contained in the ink of the present invention)
The ink of the present invention may be used alone as the quinophthalone compound, or may contain other dye compound in order to obtain a desired color tone. For example, the quinophthalone-based compound of the present invention may be mixed with a compound of a plurality of colors such as yellow, red, blue, purple and orange to give each color such as black.

Other compounds that may be contained in the ink of the present invention can be arbitrarily selected from compounds having solubility and dispersibility in the solvent used, within a range that does not impair the effects of the present invention. Is.
When the ink of the present invention is used for EWD, any compound can be selected and used as the other compound. For example, nitroso compounds, nitro compounds, monoazo compounds, disazo compounds, triazo compounds, polyazo compounds, stilbene compounds, carotenoid compounds, diarylmethane compounds, triarylmethane compounds, xanthene compounds, acridine compounds, quinoline compounds, methine compounds, thiazole compounds, Isothiazole compounds, indamine compounds, indophenol compounds, azine compounds, oxazine compounds, thiazine compounds, heterocyclic compounds, sulfur dyes, lactone compounds, hydroxyketone compounds, aminoketone compounds, anthraquinone compounds, indigo compounds, phthalocyanine compounds, pyrazole compounds, Examples include cyanovinyl compounds, natural dyes, oxidation dyes, inorganic pigments, metal complexes, carbon black and the like.

Specifically, for example, Oil Blue N (alkylamine-substituted anthraquinone), Solvent Green, Solvent Blue, Sudan Blue, Sudan Red, Sudan Yellow, Sudan Black, Disperse Vise, Disperse Red, Disperse Red, and Disperse Red. ..
Further, the ink of the present invention may contain any additive suitable for each application, if necessary, within a range that does not impair the effects of the present invention.

(EWD of the present invention)
<Structure of EWD of the present invention>
As the configuration of the electrowetting display of the present invention, a conventionally known configuration may be appropriately adopted. An example is as follows. Having a transparent electrode such as ITO on the substrate,
A water-repellent (hydrophobic) insulating film is provided thereon, and lattice-shaped partition walls are provided thereon. The portion surrounded by the partition wall is filled with the colored oil containing the ink of the present invention, and the upper portion thereof is filled with water and is bonded to the counter substrate on which the transparent electrode is formed.

<Method for producing EWD of the present invention>
As the manufacturing method of the electrowetting display of the present invention, a conventionally known manufacturing method may be appropriately adopted. An example is as follows. An appropriate resin material is applied and formed on a substrate having a transparent electrode such as ITO formed by a sputtering method, and then patterned by photolithography to form a hydrophobic insulating film and a partition member. A colored hydrophobic ink containing the ink of the present invention is added to a portion surrounded by partition walls, and a hydrophilic liquid is further added. Further, an EWD is manufactured by bonding a counter substrate having a transparent electrode such as ITO.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples unless the gist thereof is exceeded.
[Example 1]
Dye 1 which is the quinophthalone compound of the present invention used in Example 1 was synthesized as follows.

A mixed solution of 3-hydroxyl-2-methyl-4-quinolinecarboxylic acid (20.0 g), trimellitic anhydride (20.4 g) and 1,2,4-trichlorobenzene (194 mL) was heated at 170°C for 3 hours. The mixture was stirred, heated to 205° C., and stirred with heating for 10 hours. After cooling, the mixture was filtered, and the obtained solid was washed with methanol to obtain the above compound 1a (28.8 g).

A solution of the compound 1a (333 g) in o-dichlorobenzene (3230 mL) was heated to 120° C. and stirred. Bromine (192 g) was added dropwise, and the mixture was heated and stirred as it was for 8 hours. After cooling, methanol was added, and the mixture was stirred for 2 hours and then filtered. The compound 2 (335 g) was obtained by washing with methanol and water.

A mixed solution of the compound 2 (103 mg) in o-dichlorobenzene (3.5 mL) was heated to 70° C., and thionyl chloride (65 mg) was added. The mixture was heated and stirred as it was for 4 hours, di(2-ethylhexyl)amine (266 mg) was further added, and the mixture was heated and stirred for 2 hours. After allowing to cool, liquid separation operation was carried out three times with water (10 mL), and the solvent was distilled off. The crude product was purified by silica gel column chromatography (hexane/ethyl acetate=9/1 to 2/1), and the obtained solid was washed with methanol. By drying, the above-mentioned dye 1 (47 mg), which is the quinophthalone compound of the present invention, was obtained.

[Example 2]
Dye 2, which is the quinophthalone compound of the present invention used in Example 2, was synthesized as follows.

An aqueous solution of calcium hydroxide (3.3 g) (140 mL) was heated to an internal temperature of 50° C. to give compound 3
(4.8 g) was added. After heating to 80° C., chloroacetone (3.1 g) was added, and the mixture was heated with stirring at an internal temperature of 90° C. for 6 hours. The mixture was ice-cooled, and the pH was adjusted to 2.0 using a 1M aqueous hydrochloric acid solution. Compound 4 (5.0 g) was obtained by filtering and washing with water.

A mixed solution of compound 4 (4.3 g), trimellitic anhydride (3.8 g) and 1,2,4-trichlorobenzene (40 mL) was heated with stirring at 170° C. for 13.5 hours. After cooling, the mixture was filtered, and the obtained solid was washed with methanol to obtain the above compound 1b (5.4 g).

A mixed solution of compound 1b (1.5 g) in o-dichlorobenzene (13 mL) was heated to 70° C., and thionyl chloride (1.2 g) was added. The mixture was heated and stirred as it was for 2 hours, di(2-ethylhexyl)amine (4.2 g) was further added, and the mixture was heated and stirred for 1.5 hours. After allowing to cool, liquid separation operation was performed with water, and the solvent was distilled off. The crude product was purified by silica gel column chromatography (hexane/ethyl acetate=100/0 to 5/1) to obtain the above-mentioned dye 2 (0.80 g) which is the quinophthalone compound of the present invention.

[Example 3]
Dye 3, which is the quinophthalone compound of the present invention used in Example 3, was synthesized as follows.

2-Ethyl-1-hexanethiol (1.32 g) was added to an NMP mixed solution (21 mL) of compound 5 (1.49 g) and potassium carbonate (228 mg), and the mixture was heated with stirring at an internal temperature of 80 to 85°C for 8 hours. did. After allowing to cool, toluene (20 mL) and water (20 mL) were added, and the mixture was stirred. The liquid was separated once with toluene (20 mL) and three times with water (30 mL), and the solvent was distilled off. The dye 3 (1.52 g) was obtained by purifying the obtained crude product by silica gel column chromatography (hexane/ethyl acetate=3/1 to 2.5/1).

[Example 4]
Dye 4, which is the quinophthalone compound of the present invention used in Example 4, was synthesized as follows.

2-octyl-1-decylthiol (1.75 g) was added to an NMP solution (16 mL) of compound 5 (1.12 g) and potassium carbonate (171 mg), and the mixture was heated with stirring at an internal temperature of 80 to 85°C for 8 hours. did. After allowing to cool, toluene (20 mL) and water (20 mL) were added, and the mixture was stirred. The liquid was separated three times with water (15 mL), and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (hexane only to toluene/ethyl acetate=20/1) to obtain the above dye 4 (1.40 g).

[Example 5]
Dye 5, which is the quinophthalone compound of the present invention used in Example 5, was synthesized as follows.

2-Ethyl-1-hexanethiol (4.40 g) was added to an NMP mixed solution (70 mL) of compound 2 (4.12 g) and potassium carbonate (760 mg), and the mixture was heated with stirring at 80 to 85°C for 12.5 hours. did. After allowing to cool, water (20 mL) was added, and the pH was adjusted to 4 using a 1 M hydrochloric acid aqueous solution. Then, filtration was performed and washing with methanol was performed to obtain the above compound 6 (4.26 g).

A mixed solution of compound 6 (1.5 g) in o-dichlorobenzene (13 mL) was heated to 70° C., and thionyl chloride (1.2 g) was added. The mixture was heated and stirred as it was for 2 hours, di(2-ethylhexyl)amine (4.1 g) was further added, and the mixture was heated and stirred for 1 hour. After allowing to cool, liquid separation operation was performed with water, and the solvent was distilled off. The crude product was purified by silica gel column chromatography (hexane/ethyl acetate=100/0 to 5/1) to obtain the above-mentioned dye 5 (1.60 g) which is the quinophthalone compound of the present invention.

[Example 6]
Dye 6, which is the quinophthalone compound of the present invention used in Example 6, was synthesized as follows.

A mixed solution of the above compound 2 (1.24 g) in o-dichlorobenzene (10 mL) was heated to 70° C., and thionyl chloride (535 mg) was added. The mixture was heated and stirred for 4 hours as it was, 2-hexyl-1-decanol (873 mg) was further added, and the mixture was heated and stirred for 4 hours. After allowing to cool, liquid separation operation was carried out three times with water (20 mL), and the solvent was distilled off. The crude product was purified by silica gel column chromatography (hexane/ethyl acetate=100/0 to 5/1), and the obtained solid was washed with methanol. By drying, the above-mentioned dye 6 (650 mg), which is the quinophthalone compound of the present invention, was obtained.

[Comparative Example 1]
Comparative dye 1, which is the dye compound used in Comparative Example 1, was synthesized as follows.
Comparative dye 1 below was synthesized using the same method as in the synthesis method of Example 1 except that di(2-ethylhexyl)amine was changed to dipropylamine.

[Comparative example 2]
Comparative dye 2, which is an azo dye compound used in Comparative Example 2, is an azo dye corresponding to Example 2 of Patent Document 1, and was synthesized by the method described in Patent Document 1.

[Evaluation of dye solution]
1 mg of each of the dyes synthesized in Examples 1 to 6 and Comparative Example 1 was dissolved in 100 mL of n-decane. The obtained solution was added to a quartz cell having a measurement optical path length of 10 mm, and an absorption spectrum was measured with a Hitachi spectrophotometer U-4100. The absorption maximum wavelength λ _max [nm] and the molar absorption coefficient ε [L·mol ⁻¹ ·cm ⁻¹ ] were determined from the obtained spectrum.

[Measurement of saturation concentration]
The saturation concentration C of each dye with respect to n-decane was measured as follows.
Each of the dyes synthesized in Examples 1 to 6 and Comparative Example 1 was added to n-decane until a dissolved residue was generated, and the mixture was sonicated at 30°C for 30 minutes. After the addition, each was sonicated at 30° C. for 30 minutes. After standing at 5° C. for 24 hours, it was subjected to centrifugal filtration with a 0.1 micron filter using a microcentrifuge (centrifugal force 5200×g). The obtained saturated solution is diluted to an appropriate concentration, and the absorption spectrum is measured with a Hitachi spectrophotometer U-4100 using a quartz cell with a measurement optical path length of 10 mm to obtain the absorption maximum wavelength absorption maximum wavelength λ _max. The concentration of each compound was calculated from the relationship between the absorbance at [nm] and the previously measured molar extinction coefficient ε [L·mol ⁻¹ ·cm ⁻¹ ], and the saturation concentration C [mol·L ⁻¹ ] was calculated. Further, the value of the product εC of the molar extinction coefficient ε [L·mol ⁻¹ ·cm ⁻¹ ] and the saturation concentration C [mol·L ⁻¹ ] was obtained. The evaluation results are shown in Table 4.

As shown in Table 4, it was found that the compound of the present invention was dissolved in decane which is a low polar solvent, and the product εC with the molar absorption coefficient ε was significantly improved. This indicates that it is useful as a material for optical shutters, a display material, particularly an electrowetting display material, an electrophoretic display material.

[Light resistance test]
Using each of the dye compounds synthesized in Examples 1 to 6 and Comparative Example 2, a 0.2 wt% n-decane solution was prepared, placed in a cell having an optical path length of 10 μm, and sealed with an epoxy resin. Each sample for measurement was produced. These samples were irradiated with xenon light (340 nm 0.55 W/m ² irradiance) for 40 hours using a weather meter (Atlas Ci4000). During irradiation, the temperature inside the test tank of the weather meter was maintained at 33°C. The residual rate of each dye compound was calculated by the following formula. The results are shown in Table 5.

As a result, the residual dye ratio of each of Examples 1 to 6 was a very high value of 97% or more, while the residual dye ratio of Comparative Example 2 was 90%. That is, it was found that the quinophthalone compound of the present invention has better light resistance than conventional azo compounds.

INDUSTRIAL APPLICABILITY The quinophthalone compound of the present invention has excellent solubility in a low-polarity solvent and excellent light resistance, and is useful as a dye compound for EWD and the like.

Claims (11)

An ink containing a solvent having a relative dielectric constant of 3 or less at 22° C. at a measurement frequency of 1 kHz and a solubility of 20 mg/L or less in water at 25° C., and a quinophthalone compound represented by the following general formula (1). ..

(In the formula, R ^{1 to} R ⁶ each independently represent a hydrogen atom, an alkyl group which may have a substituent, a halogen group, an alkylthio group, an alkyloxy group, an alkylamino group or a hydroxyl group. ^At least one of ^{1 to} R ⁶ represents a hydroxyl group , R ² is an alkylthio group, and the alkyl moiety of the alkylthio group is a branched chain having 4 or more carbon atoms which may have a substituent. alkyl, ^R 7 ^{to R 10} each independently represent a hydrogen atom, an optionally substituted alkyl group, COOR ^{11 group, CONR} 12 ^{R 13} _group, SO ^{2 R 14} group or _SO 2 ^{NR 15} R ¹⁶ groups are represented, and R ^{11 to} R ¹⁶ represent a linear or branched alkyl group which may have a substituent.) R ¹ and R ^{3 to} R ⁶ are each independently a hydrogen atom, an alkyl group which may have a substituent, a halogen group or a hydroxyl group, and R ^{11 to} R ^{16 each} have a substituent. The ink according to claim 1, which represents an optionally branched alkyl group. The ink according to claim ¹ , wherein any one of R ¹ and R ^{3 to} R ⁶ is an alkylthio group, an alkyloxy group, or an alkylamino group. The ink according to any one of claims 1 to 3 , wherein at least one of R ^{7 to} R ¹⁰ is a COOR ¹¹ group or a CONR ¹² R ¹³ group. The ink according to any one of claims 1 to 4 , wherein the halogen group is a bromine atom. The ink according to any one of claims 1 to 5 , wherein R ^{11 to} R ¹⁶ are branched alkyl groups having 4 or more carbon atoms and optionally having a substituent. An electrowetting display comprising the ink according to any one of claims 1 to 6 . A quinophthalone compound represented by the following general formula (1).

(In the formula, R ^{1 to} R ⁶ each independently represent a hydrogen atom, an alkyl group optionally having a substituent, a halogen group, an alkylthio group, an alkyloxy group, an alkylamino group or a hydroxyl group. , R ^{1 to} R ⁶ represent at least one hydroxyl group, and R ² is an alkylthio group, and the alkyl moiety of the alkylthio group has 4 or more carbon atoms which may have a substituent. a branched alkyl, ^R 7 ^{to R 10} each independently represent a hydrogen atom, an alkyl group having a substituent, COOR ^{11 group, CONR} 12 ^{R 13} _group, SO ^{2 R 14} group or _SO 2 ^NR 15 ^{R 16} Group, but at least one of R ^{7 to} R ¹⁰ represents a COOR ¹¹ group or a CONR ¹² R ¹³ group, and R ^{11 to} R ¹⁶ represent a linear or branched alkyl group which may have a substituent. Represents.) R ¹ and R ^{3 to} R ⁶ are each independently a hydrogen atom, an alkyl group which may have a substituent, a halogen group or a hydroxyl group, and R ^{11 to} R ^{16 each} have a substituent. The quinophthalone-based compound according to claim 8 , which represents an optionally branched alkyl group. The quinophthalone compound according to claim 8 , wherein any of R ¹ and R ^{3 to} R ⁶ is an alkylthio group, an alkyloxy group or an alkylamino group. The quinophthalone compound according to any one of claims 8 to 10 , wherein the halogen group is a bromine atom.