JP5853601B2 - Benzothiazole compound and ink containing the compound - Google Patents

Description

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

  In the electrowetting display, a plurality of pixels filled with two phases of an aqueous medium and oil-based colored ink are arranged on a substrate, and the affinity of the interface of the aqueous medium / oil-based colored ink is determined by on-off of voltage application for each pixel. This is an image display format performed by controlling oil and developing / aggregating oil-based colored ink on the substrate (Non-patent Document 1). A dye used for an electrowetting display is required to have high solubility in a solvent (Patent Document 1).

Patent Document 2 describes a benzothiazole dye having excellent performance in color density and color tone as a dye for thermal transfer recording. In Patent Document 3, an azo compound having an absorption maximum wavelength of 450 to 630 nm is shown in the recording layer of the optical recording medium, and a benzothiazole compound is exemplified as a compound exhibiting good recording characteristics.
Patent Document 4 discloses an azo dye having excellent heat resistance in order to improve clogging of a discharge hole due to scorching of a transfer portion in a non-contact type thermal transfer recording system. The dye is shown.

Special table 2007-531917 gazette JP-A-10-204307 JP-A-8-108625 JP 2000-280635 A

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

In Patent Documents 2 and 3 described above, although there are descriptions of compounds preferable for thermal transfer recording or as an optical recording medium, the solubility in a specific solvent, particularly a low-polar solvent, and the physical properties of the solvent are not studied.
In Patent Document 4, although preferable conditions such as boiling point as a solvent are described, there is no description or suggestion about solubility in a low polarity solvent.

  An object of the present invention is to provide a benzothiazole compound having excellent solubility in a low polar solvent and having a high extinction coefficient, and an ink using the compound.

As a result of intensive studies to solve the above problems, the present inventors have found that a benzothiazole compound having a certain chemical structure is excellent in solubility in a low polarity solvent such as a hydrocarbon solvent and has a high molar absorption. It was found to have a coefficient. The present invention has been accomplished based on these findings.
That is, the gist of the present invention is as follows (1) to (1 2 ).
(1) An ink comprising a solvent having a relative dielectric constant of 2.2 or less at a measurement frequency of 1 KHz and a boiling point of 115 ° C. or more, and a benzothiazole compound, wherein the benzothiazole compound has the following general formula (I):

[In general formula (I),
R ¹ and R ² each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent or an aryl group having 6 to 20 carbon atoms which may have a substituent,
A represents a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or a —COOR ³ group;
R ³ represents an alkyl group having 1 to 20 carbon atoms,
m represents an integer of 0 to 4, and when m is 2 or more, two or more A in one molecule may be the same or different,
A ′ represents an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted alkoxy group having 1 to 10 carbon atoms, or —NHCOR ⁴ group;
R ⁴ represents an alkyl group having 1 to 10 carbon atoms,
n represents an integer of 0 to 4, and when n is 2 or more, A ′ present in 2 or more in one molecule may be the same or different.
Ink represented by
(2) The ink according to (1), wherein the solvent contains at least one linear or branched aliphatic hydrocarbon solvent .
(3) When the benzothiazole compound is dissolved in n-decane, the absorption maximum wavelength in the 350 to 750 nm wavelength region is in the range of 450 to 600 nm, and the molar extinction coefficient ε ( Lmol ⁻¹ cm ⁻¹ ) and a compound εC of a saturated solution concentration C (mol L ⁻¹ ) in the same solvent at room temperature (25 ° C.) is a compound having a value of 500 cm ⁻¹ or more (1) or (2 ) Ink.
(4) The ink according to any one of (1) to (3), further including at least one selected from the group consisting of a heterocyclic compound and an anthraquinone compound.
(5) The ink according to (4), wherein the heterocyclic compound contains at least one of the following general formulas (II), (III), and (IV).

[In the general formula (II),
R ¹⁰¹ represents an alkyl group having 2 to 10 carbon atoms which may have a substituent,
R ¹⁰² represents an alkyl group having 3 to 10 carbon atoms which may have a substituent,
The phenylene group and the phenyl group may have a substituent. ]

[In general formula (III),
R ²⁰¹ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ²⁰² represents a cyano group or a —COOR ²⁰⁹ group,
R ²⁰⁹ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ²⁰³ and R ²⁰⁴ each independently represent an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ²⁰⁵ , R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ each independently have a hydrogen atom, a halogen atom, a substituent, or an alkyl group having 1 to 20 carbon atoms or a substituent. An alkoxy group having 1 to 20 carbon atoms or a —NHCOR ²¹⁰ group;
R ²¹⁰ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms,
X ¹ represents a nitrogen atom or a methine group which may have a substituent,
R ²⁰³ and R ²⁰⁴ may be bonded to each other to form a ring structure.

[In general formula (IV),
R ³⁰¹ and R ³⁰² each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
D represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted alkoxy group having 1 to 10 carbon atoms, or a —NHCOR ³⁰⁵ group. Indicate
R ³⁰⁵ may have an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. An aryl group having 6 to 20 carbon atoms;
e represents an integer of 1 to 4, and when e is 2 or more, D present in 2 or more in one molecule may be the same or different,
R ³⁰³ has 1 to 1 carbon atoms which may have a hydrogen atom, a halogen atom, a cyano group, or a substituent.
10 represents an alkyl group, an aryl group having 6 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 10 carbon atoms which may have a substituent or a -COOR ³⁰⁶ group;
R ³⁰⁶ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent,
R ³⁰⁴ is an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, and an optionally substituted carbon number. An alkenyl group having 2 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms which may have a substituent, an alkoxycarbonyl group having 2 to 20 carbon atoms which may have a substituent, an aldehyde group, R ³⁰⁷ OOC (NC) C═CH— group, NC (NC) C═CH— group or a group represented by the following general formula (V):

R ³⁰⁷ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
D ′ is a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or -COOR represents ³⁰⁸ groups,
g represents an integer of 1 to 5, and when g is 2 or more, two or more D's in one molecule may be the same or different,
R ³⁰⁸ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent,
X ² represents a nitrogen atom or a methine group optionally having a halogen atom, a cyano group or —COOR ³⁰⁹ as a substituent,
R ³⁰⁹ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent.
(6) The ink according to (4) or (5), wherein the anthraquinone compound is a compound represented by the following general formula (IV).

[In general formula (VI),
L has a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, and a substituent. An alkylsulfanyl group having 1 to 20 carbon atoms, cyano group, hydroxy group, amino group, nitro group, —COOR ⁴⁰¹ group, —NHR ⁴⁰² group or —NHCOR ⁴⁰³ group, which may have
R ⁴⁰¹ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ⁴⁰² may have a substituent and may have a C 1-20 alkyl group, a substituent may have a C 1-20 alkoxy group, or a substituent. An aryl group having 6 to 20 carbon atoms;
R ⁴⁰³ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
t represents an integer of 1 to 4, and when t is 2 or more, L present in 2 or more in one molecule may be the same or different,
L ′ represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. An alkylsulfanyl group having 1 to 20 carbon atoms which may have, a cyano group, a hydroxy group, an amino group,
A nitro group, -COOR ⁴⁰⁴ group, -NHR ⁴⁰⁵ group or -NHCOR ⁴⁰⁶ group,
R ⁴⁰⁴ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ⁴⁰⁵ may have an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. A good aryl group having 6 to 20 carbon atoms,
R ⁴⁰⁶ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
q represents an integer of 1 to 4, and when q is 2 or more, L ′ present in 2 or more in one molecule may be the same or different. ]
(7) The ink according to any one of (1) to (6), which is used for a display or an optical shutter.
(8) A display having a display part containing the ink according to any one of (1) to (7) and displaying an image by controlling voltage application of the display part.
(9) The display according to (8), wherein the display portion includes electrophoretic particles or an aqueous medium.
(10) The display according to (8) or (9), wherein an image is displayed by changing a coloring state by voltage application.
(11) The display according to any one of (8) to (10), wherein an image is displayed by an electrowetting method or an electrophoresis method.
(12) An electronic paper having the display according to any one of (8) to (11) .

The benzothiazole compounds of the present invention can be widely used as inks because they have high solubility in oil-soluble solvents. Furthermore, since the ink containing the benzothiazole compound of the present invention has both high solubility in a low-polar solvent and a high molar extinction coefficient, it is useful for inks used for displays and optical shutters.
Furthermore, the display has a display part containing ink, a display that displays an image by controlling voltage application of the display part, a display that displays an image by changing a coloring state by voltage application, It is particularly useful for a display that displays using migrating particles or an aqueous medium.

Here, the electrophoretic particles are charged particles, may have a color, and may include a plurality of types of electrophoretic particles in the display region. The aqueous medium is a fluid that may have a color, and may have a plurality of types of aqueous medium at the display site.
The benzothiazole compounds and inks of the present invention are particularly useful as inks used in electrowetting display or electrophoretic display.

The ink of the present invention can also provide a good ink excellent in hue such as red and black by combining with the benzothiazole compound of the present invention and another compound, and functions as an optical shutter. It is also useful as a member.
Any display device having a display can be used, but it is particularly useful when used for electronic paper.

Hereinafter, typical embodiments for carrying out the present invention will be specifically described. However, the present invention is not limited to the following embodiments as long as the gist of the present invention is not exceeded, and various modifications may be made. Can do.
The ink of the present invention is an ink containing a solvent having a relative dielectric constant of 3 or less at a measurement frequency of 1 KHz and a boiling point of 115 ° C. or more and a benzothiazole compound, and the benzothiazole compound has the following general formula: (I):

[In general formula (I),
R ¹ and R ² each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent or an aryl group having 6 to 20 carbon atoms which may have a substituent,
A represents a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or a —COOR ³ group;
R ³ represents an alkyl group having 1 to 20 carbon atoms,
m represents an integer of 0 to 4, and when m is 2 or more, two or more A in one molecule may be the same or different,
A ′ represents an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted alkoxy group having 1 to 10 carbon atoms, or —NHCOR ⁴ group;
R ⁴ represents an alkyl group having 1 to 10 carbon atoms,
n represents an integer of 0 to 4, and when n is 2 or more, A ′ present in 2 or more in one molecule may be the same or different.
It is an ink represented by

(solvent)
The solvent used in the ink of the present invention has a relative dielectric constant of 3 or less at a measurement frequency of 1 kHz, and the “low polarity solvent” in the present invention has the above meaning. The ink of the present invention has layers such as a water layer and an oil layer, for example, and breaks up the layer or moves the layer.
aside). In order to make the display clear, it is necessary that the layer containing the ink and the other layer do not mix and stably split or move, and the solvent has low compatibility with the other layer, Low polarity is required. In the present invention, by including a specific solvent and a benzothiazole-based compound in the ink, the layer can be stably split or moved.

Further, in a display using electrophoresis in which charged particles (electrophoretic particles) in a solvent move by an electric field, driving may be hindered if the dielectric constant of the solution is large. By using the solvent of the present invention and a specific benzothiazole compound, the solution can be colored without hindering the movement of the particles.
In addition, when the ink of the present invention is used in an electrowetting display, solvent wettability, contact angle, and surface tension may affect the drive of the display.

The relative dielectric constant of the solvent used in the present invention is 3 or less at a measurement frequency of 1 kHz. More preferably, it is 2.5 or less, More preferably, it is 2.2 or less. The lower limit of the relative dielectric constant is not particularly limited, but is usually 1.5 or more, preferably 1.7 or more. The method for measuring the relative dielectric constant of the solvent is shown in the Examples.
If the relative dielectric constant of the layer containing the ink is too large, the display device may be hindered. For example, if the other layer that does not contain ink is an electrically conductive or polar liquid such as water or a salt solution, the layer will be mixed if the relative permittivity of the solvent used in the ink is too high. There is a case.

  The boiling point of the solvent of the present invention is 115 ° C. or higher. Moreover, it is preferable that it is 130 degreeC or more, and it is more preferable that it is 150 degreeC or more. Moreover, it is preferable that it is 300 degrees C or less. If the boiling point is not too high, the melting point and viscosity of the solvent will not be too high, and it may be possible to drive the display device without hindering it. Also, if the boiling point is not too low, volatility can be suppressed and stability can be maintained. And safety may be obtained.

The viscosity of the solvent used in the present invention is not particularly limited, but the viscosity when the solvent temperature is 25 ° C. is preferably 0.1 m ² s ⁻¹ or more. Further, it is preferably 10,000 mm ² s ⁻¹ or less, more preferably 2000 mm ² s ⁻¹ or less, and 1000 mm ^2.
It is particularly preferred that it is s ⁻¹ or less. When the viscosity of the solvent is not too high, the compound or the like is easily dissolved, and the display device may be driven without causing any trouble. The method for measuring the viscosity of the solvent of the present invention is shown in the Examples.

  The solvent of this invention can be used individually or in mixture. Specific examples include hydrocarbon solvents, fluorocarbon solvents, silicone oils and higher fatty acid esters. Examples of the hydrocarbon solvent include linear or branched aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and petroleum naphtha. Examples of the aliphatic hydrocarbon solvent include aliphatic hydrocarbon solvents such as n-decane, isodecane, decalin, nonane, dodecane, isododecane, tetradecane, hexadecane, isoalkanes, etc., and commercially available products include Isopar E, Examples include Isopar G, Isopar H, Isopar L, Isopar M (manufactured by Exxon Mobil Corporation), IP Solvent (manufactured by Idemitsu Petrochemical Co., Ltd.), Saltol (manufactured by Philips Petroleum Corporation), and the like. Examples of the aromatic hydrocarbon solvent include Hysozol (manufactured by Nippon Oil Co., Ltd.), and examples of the petroleum naphtha solvent include Shell S.I. B. R. Shellzol 70, Shellzol 71 (manufactured by Shell Petrochemical Co., Ltd.), Pegazole (manufactured by Exxon Mobil Corporation), and the like.

The fluorocarbon-based solvent is mainly a fluorine-substituted hydrocarbon, and examples thereof include perfluoroalkanes represented by C _n F _{2n + 2} such as C ₇ F ₁₆ and C ₈ F ₁₈ . Fluorinert PF5080, Fluorinert PF5070 (manufactured by Sumitomo 3M) and the like are listed. Fluorinated inert liquids such as Fluorinert FC series (manufactured by Sumitomo 3M), fluorocarbons as Krytox GPL series (manufactured by DuPont Japan Limited), and chlorofluorocarbons as HCFC-141b (manufactured by Daikin Industries, Ltd.) ), F (CF ₂ ) ₄ CH ₂ CH ₂ I, iodinated fluorocarbons such as F (CF ₂ ) 6 I include I-1420, I-1600 (manufactured by Daikin Fine Chemical Research Laboratories), 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). The above-mentioned solvents can be used alone or in combination.
Preferably, the solvent includes one or more selected from hydrocarbon solvents, fluorocarbon solvents, and silicone oils. The content is usually 50% by mass or more of the low polarity solvent, preferably 70% by mass or more, and more preferably 90% by mass or more.

The ink of the present invention contains a low polarity solvent and a benzothiazole compound, and is obtained by dissolving a benzothiazole compound and other compounds and additives used as necessary in a low polarity solvent. .
Here, the dissolution means that the benzothiazole compound does not need to be completely dissolved in the low polarity solvent, the solution dissolved in the low polarity solvent passes through a filter of about 0.1 micron, and the extinction coefficient is It may be in a state where it can be measured, and may be in a state where fine particles of the compound are dispersed.

(Benzothiazole compounds)
The benzothiazole compound of the present invention has a chemical structure represented by the general formula (I) described above.
Specific examples of R ^{1 to} R ⁴ , A, A ′, n, and m used in the general formula (I) will be described below.
In the general formula (I), R ¹ and R ² each independently has an alkyl group having 1 to 20 carbon atoms which may have a substituent or a carbon number which may have a substituent. 6 to 20 aryl groups are shown.

Examples of the alkyl group which may have a substituent for R ¹ and R ² include 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, a decyl group, Linear alkyl group such as dodecyl group; branched alkyl group such as isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, 2-ethylbutyl, 2-ethylhexyl, isooctyl group, isononyl group, etc .; cyclopropyl group, Examples thereof include cyclic alkyl groups such as cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, cyclohexylmethyl group and 4-butylmethylcyclohexyl group. The alkyl group for R ¹ and R ² preferably has 2 or more carbon atoms, and more preferably 4 or more carbon atoms. Moreover, it is preferable that carbon number is 16 or less, and it is further more preferable that it is 12 or less.

As the aryl group which may have a substituent for R ¹ and R ² , one hydrogen atom is removed from a 5- or 6-membered monocyclic ring or a condensed ring formed by condensing 2 to 4 thereof. Specific examples include aromatic hydrocarbon ring groups or aromatic heterocyclic groups such as phenyl group, tolyl group, xylyl group, mesityl group naphthyl group, thienyl group, pyridyl group, etc. The number is preferably 6 or more, the carbon number is preferably 16 or less, and more preferably 12 or less.

When the number of carbon atoms of R ¹ and R ² is in the above range, the molecular weight does not become too large and the gram extinction coefficient may not be deteriorated.
R ¹ and R ² may be bonded to form a cyclic structure, or (A ′) _n may be bonded to form a ring structure.
Specific examples of the substituent that the alkyl group of R ¹ and R ² may have are preferably a low-polar substituent group because of its solubility in a low-polar solvent, such as a fluorine atom, a chlorine atom, a bromine atom, Halogen atoms such as iodine atom; alkoxy groups having 1 to 20 carbon atoms such as methoxy group, ethoxy group, propoxy group, butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group; methoxycarbonyl group, ethoxycarbonyl group And an alkoxycarbonyl group having 2 to 20 carbon atoms such as a t-butoxycarbonyl group; a cyano group and the like.

Moreover, as a specific example of the substituent which the aryl group of R ¹ and R ² may have, a low-polar substituent is preferable because of its solubility in a low-polar solvent. Examples include 20 alkyl groups, alkoxy groups having 1 to 20 carbon atoms, alkoxycarbonyl groups having 2 to 20 carbon atoms, and cyano groups.
(A) A in _m represents a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or a —COOR ³ group.

The alkyl group having 1 to 20 carbon atoms which may have a substituent of A is synonymous with the alkyl group exemplified for R ¹ , and the substituent which the alkyl group of A may have is also R It is synonymous with the substituent which the alkyl group illustrated in ¹ may have. The alkyl group of A preferably has 2 or more carbon atoms, and more preferably has 4 or more carbon atoms. Moreover, it is preferable that carbon number is 16 or less, and it is further more preferable that it is 12 or less. When the carbon number is in the above range, the molecular weight does not become too large, and the gram extinction coefficient may not be deteriorated.

R ³ represents an alkyl group having 1 to 20 carbon atoms. Specific examples of the alkyl group for R ^{3 have} the same meaning as the alkyl group exemplified for R ¹ . The alkyl group for R ³ preferably has 2 or more carbon atoms, more preferably 4 or more carbon atoms. Moreover, it is preferable that carbon number is 16 or less, and it is further more preferable that it is 12 or less. When the carbon number is in the above range, the molecular weight does not become too large, and the gram extinction coefficient may not be deteriorated.

m represents an integer of 0 to 4, and when m is 2 or more, two or more A present in one molecule may be the same or different. Preferably, the solubility may be improved when m is 1 or more.
(A ′) A ′ in _n is an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkoxy group having 1 to 10 carbon atoms which may have a substituent, or —NHCOR. ⁴ groups are shown.

The alkyl group having 1 to 10 carbon atoms which may have a substituent for A ′ has the same meaning as the alkyl group having 1 to 10 carbon atoms among the alkyl groups exemplified for R ¹ . Specific examples of the substituent that the alkyl group A ′ may have include a halogen atom, an alkoxy group having 1 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, a cyano group, and the like. Can be mentioned. Examples of the alkoxy group having 1 to 10 carbon atoms which may have a substituent of A ′ include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group. Linear alkoxy groups such as a group, nonyloxy group, decyloxy group; branched-chain alkoxy groups such as isopropoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, isooctyloxy group; cyclopropoxy group, cyclopentyloxy group And an alkoxy group having a cycloalkane structure such as a cyclohexyloxy group and a cyclopropylmethyloxy group. Specific examples of the substituent that the alkoxy group A ′ may have include, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, a formyl group, an acetyl group, a benzozoyl group, a carbazoyl group, and a phenyl group. C1-C10 carbonyl groups, such as a carbonyl group, etc. are mentioned.

R ⁴ represents an alkyl group having 1 to 10 carbon atoms, and is specifically synonymous with the alkyl group exemplified for A ′.
Further, A ′ is a hydrogen atom; halogen atom; methyl group, ethyl group, propyl group, isopropyl group, cyclopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group and the like. NHCOR ⁴ groups such as an alkyl group; an alkoxy group and an acetylamino group are preferred, and a methyl group, an alkoxy group and an acetylamino group are particularly preferred.

n represents an integer of 0 to 4, and when n is 2 or more, two or more A's in one molecule may be the same or different. Preferably, the solubility may be improved when n is 1 or more.
In terms of industrial production, the compound of the present invention preferably satisfies the conditions such as good crystallinity, easy purification, few production steps, and easy availability of raw materials.

  Specific examples of the benzothiazole compound represented by the general formula (I) are shown below. The present invention is not limited to these unless it exceeds the gist.

When the benzothiazole compound of the present invention has a substituent, the molecular weight including the substituent is preferably 3000 or less, and more preferably 1500 or less. Moreover, it is preferable that it is 400 or more, and it is more preferable that it is 500 or more. If the molecular weight is too large, the gram extinction coefficient may be low.
The benzothiazole compounds represented by the general formula (I) are, for example, JP-A-10-204.
It can be synthesized according to the methods described in JP-A No. 307 and JP-A No. 2000-280635.

  The benzothiazole-based compound of the present invention is characterized by excellent solubility in a low polarity solvent. The solubility of the benzothiazole compound of the present invention in n-decane at room temperature (25 ° C.) is usually 1% by mass or more, preferably 3% by mass or more, and more preferably 5% by mass or more. The higher the solubility, the better, but it is usually about 80% by mass or less. When the solubility is equal to or higher than a specific value, display on a display device such as a display may be possible.

  When the benzothiazole compound of the present invention is used in an electrowetting display, it is desirable that it is water-insoluble in terms of its principle. Here, “water-insoluble” means that the solubility in water at 25 ° C. and 1 atm is 0.1% by mass or less, preferably 0.01% by mass or less. The benzothiazole compound of the present invention exhibits a red color tone. When the compound is dissolved in a low polarity solvent, the absorption maximum wavelength in the 380 to 780 nm wavelength region is preferably in the range of 600 to 700 nm, and when dissolved in n-decane, the absorption in the 380 to 780 nm wavelength region is absorbed. The maximum wavelength is preferably in the range of 600 to 700 nm.

The molar extinction coefficient is preferably 10,000 (Lmol ⁻¹ cm ⁻¹ ) or more, and more preferably 40000 (Lmol ⁻¹ cm ⁻¹ ) or more in order to satisfy the display performance.
Furthermore, benzothiazole compounds of the present invention, when dissolved in n- decane, molar extinction coefficient at the absorption maximum wavelength in the solution epsilon - and (L mol ^{1 cm -1),} at room temperature (25 ° C.) in the same solvent The value of the product εC of the concentration C (molL ⁻¹ ) of the saturated solution in is usually 500 cm ⁻¹ or more, preferably 1000 cm ⁻¹ or more, more preferably 2000 cm ⁻¹ or more. A higher εC value is preferable for high light resistance, and there is no particular upper limit, but it is usually 40000 cm ⁻¹ or less.

  About the density | concentration of the benzothiazole type compound in the ink of this invention, it prepares by arbitrary density | concentrations according to the objective. For example, when used as a blue pigment for an electrowetting display, it is usually used at a concentration of 1% by mass or more, diluted in a solvent according to the required εC value, preferably 3% by mass or more, and more preferably Is 5% by mass or more. The concentration is preferably higher, but is usually about 80% by mass or less.

The ink of the present invention may contain the above benzothiazole compound alone, or may contain two or more kinds in any combination and ratio.
The benzothiazole compound of the present invention is useful as an optical shutter material, a display material, particularly an electrowetting display material, and an electrophoretic display material because it has excellent solubility in a low-polarity solvent and has a high extinction coefficient. is there.

The lower limit of the ink viscosity when the ink temperature of the present invention is 25 ° C. is not particularly limited, but it is usually preferably 0.1 m ² s ⁻¹ or more. The upper limit is preferably not more than 10000 m ² s ^-1, more preferably 2000 m ² s ^-1 or less, particularly preferably 1000 m ² s ^-1 or less. If the viscosity of the ink is too large, the display may be hindered. The method for measuring the viscosity of the ink of the present invention is shown in Examples.

The relative permittivity and viscosity of the solvent of the present invention and the ink containing the solvent and the pigment are preferably smaller in the difference between the solvent and the ink because the influence on the driving characteristics when used in a display device is reduced. . Therefore, the ink of the present invention may contain any additive suitable for each application as necessary, as long as the effect of the present invention is not impaired, but does not change the characteristics of the solvent. It is preferable.

(Other compounds)
The ink of the present invention may contain other compounds in addition to the above benzothiazole compounds in order to obtain a desired color tone. For example, the benzothiazole-based compound of the present invention can be mixed with other compounds to give red and other colors, or a mixture of compounds of multiple colors such as blue, yellow, red, purple, and orange And can be 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 medium to be used within a range not impairing the effects of the present invention. It is.
When the ink of the present invention is used for an electrowetting display, any other compound can be selected and used. For example, heterocyclic compounds, anthraquinone compounds, nitroso compounds, nitro compounds, monoazo compounds, disazo compounds, triazo compounds, polyazo compounds, stilbene compounds, carotenoid compounds, diarylmethane compounds, triarylmethane compounds, xanthene compounds, acridine compounds, quinolines Compound, methine compound, thiazole compound, indamine compound, indophenol compound, azine compound, oxazine compound, thiazine compound, heterocyclic compound, sulfur dye, lactone compound, hydroxyketone compound, aminoketone compound, anthraquinone compound, indigo compound, phthalocyanine compound, Natural dyes, oxidation dyes, inorganic pigments, metal complexes and the like can be listed.

Specifically, for example, Oil Blue N (alkylamine-substituted anthraquinone), Solvent Green, Solvent Blue, Sudan Blue, Sudan Red, Sudan Yellow, Sudan Black; compounds described in International Publication No. 2009-063880; Compounds described in No. 031860; and the like. These compounds are known per se and are commercially available.

Among these, it is preferable to include at least one selected from the group consisting of a heterocyclic compound and an anthraquinone compound, and a preferable ink can be realized by arbitrarily combining them.
Specific examples of the heterocyclic compound are not particularly limited, but preferably include at least one of the following general formulas (II), (III), and (IV).

  Examples of the heterocyclic compound include compounds represented by the following general formula (II).

In General Formula (II), R ¹⁰¹ represents an alkyl group having 2 to 10 carbon atoms which may have a substituent, and R ¹⁰² has 3 to 10 carbon atoms which may have a substituent. An alkyl group is shown.
As the alkyl group of R ¹⁰¹ , among the alkyl groups exemplified as A ′ in the general formula (I), the alkyl group having the carbon number of 2 to 10 is synonymous with the alkyl group of R ¹⁰¹ as an ethyl group, propyl A straight-chain alkyl group having 2 to 6 carbon atoms of the group, butyl group, pentyl group and hexyl group is particularly preferable.

R < ¹⁰² > is synonymous with the C3-C10 alkyl group among the alkyl groups illustrated by A '. R ¹⁰² is preferably an alkyl group having 3 to 6 carbon atoms in view of a high gram extinction coefficient and availability of raw materials. The preferred branched alkyl group from the viewpoint of solubility in non-polar solvents, as R ¹⁰² has tert- butyl group is most preferred.
R ¹⁰¹ and R ¹⁰² may have an arbitrary substituent. As an example of an arbitrary substituent, a substituent that does not prevent solubility in a low-polar solvent is preferable, and examples thereof include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  In general formula (II), the phenyl group and the phenylene group may each independently have a substituent. As the substituent that the phenyl group may have, a nonpolar substituent is preferable from the viewpoint of solubility in a nonpolar organic solvent such as a hydrocarbon solvent, and an alkyl group having 1 to 10 carbon atoms, carbon Examples include an alkoxy group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, and a haloalkoxy group having 1 to 10 carbon atoms. Among them, an alkyl group having 1 to 10 carbon atoms and / or a carbon number. Is preferably an alkoxy group having 1 to 10.

  As the alkyl group having 1 to 10 carbon atoms and the alkoxy group of the substituent which the phenyl group may have, the alkyl group and alkoxy group having 1 to 10 carbon atoms exemplified by A ′ in the general formula (I) and It is synonymous. As the haloalkyl group and haloalkoxy group of the substituent which the phenyl group may have, the above alkyl group and alkoxy group are groups in which a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom is substituted Specifically, a trifluoromethyl group, a pentafluoroethyl group, a nonafluorobutyl group, a trifluoromethoxy group, and the like can be given.

  Examples of the substituent that the phenylene group may have include the same groups as those listed above as the substituent of the phenyl group, and among them, an alkyl group having 1 to 10 carbon atoms and / or a carbon number of 1 to 10 carbon atoms. And particularly preferable substituents include, for example, an alkyl group having 1 to 4 carbon atoms such as a methyl group and an ethyl group, and an alkoxy group having 1 to 4 carbon atoms such as a methoxy group and an ethoxy group.

  Specific examples of the compound represented by the general formula (II) are shown below, but the present invention is not limited to these unless it exceeds the gist.

The compound represented by the general formula (II) can be synthesized, for example, according to the method described in International Publication No. 2009/063880.
Examples of the heterocyclic compound include compounds represented by general formula (III) below.

In general formula (III),
R ²⁰¹ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ²⁰² represents a cyano group or a —COOR ²⁰⁹ group, R ²⁰⁹ represents an optionally substituted alkyl group having 1 to 20 carbon atoms,
R ²⁰³ and R ²⁰⁴ each independently represent an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ²⁰⁵ , R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ each independently have a hydrogen atom, a halogen atom, a substituent, or an alkyl group having 1 to 20 carbon atoms or a substituent. An alkoxy group having 1 to 20 carbon atoms or a —NHCOR ²¹⁰ group, wherein R ²¹⁰ may have a hydrogen atom, a substituent, or an alkyl group having 1 to 20 carbon atoms, or a substituent; An alkoxy group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms which may have a substituent;
X ¹ represents a nitrogen atom or a methine group which may have a substituent.

The alkyl group having 1 to 20 carbon atoms which may have a substituent of R ²⁰¹ has the same meaning as the alkyl group exemplified for R ¹ in formula (I), and the substituent which may have have alkyl groups exemplified for R ¹ of the general formula (I) is synonymous with the substituent that may. R ²⁰¹ may combine with X ¹ to form a cyclic structure.
R ²⁰¹ is preferably a substituent having a small molecular weight from the viewpoint of the Gram extinction coefficient, and more preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R ²⁰¹ is preferably an unsubstituted alkyl group from the viewpoint of production, and is an unsubstituted alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, or a butyl group. More preferably, it is a group.

R ²⁰² represents a cyano group or a —COOR ²⁰⁹ group, and R ²⁰⁹ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent. Alkyl group R ²⁰⁹ has the same meaning as the alkyl groups exemplified for R ¹ of the general formula (I), substituent which may be possessed by the alkyl group is as defined. R ²⁰⁹ is preferably an alkyl group having 1 to 10 carbon atoms from the viewpoint of production or Gram extinction coefficient.

R ²⁰³ and R ²⁰⁴ each independently represent an alkyl group having 1 to 20 carbon atoms which may have a substituent. R ²⁰³ and R ²⁰⁴ may combine to form a cyclic structure. R ²⁰³ or R ²⁰⁴ may be bonded to R ²⁰⁶ and R ²⁰⁷ to form a ring structure.
R ²⁰⁵ , R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ may each independently have a hydrogen atom, a halogen atom, a substituent, or an alkyl group having 1 to 20 carbon atoms or a substituent. A -NHCOR ²¹⁰ group which may have a good alkoxy group having 1 to 20 carbon atoms or a substituent is shown.

Specific examples of the alkyl group represented by R ²⁰⁵ , R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ are the same as the alkyl group exemplified for R ¹ in the general formula (I), and the substituent that the alkyl group may have It is synonymous. Specific examples of the alkoxy group of R ²⁰⁵ , R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ include a phenoxy group, a naphthyloxy group, a dodecanoxy group, a toximethyl in addition to the alkoxy group exemplified by A ′ in the general formula (I). And linear, branched, and cyclic alkoxy having 1 to 20 carbon atoms such as a group, methoxyethyl group, methoxybutyl group, ethoxymethyl group, ethoxyethyl group, and ethoxybutyl group. Specific examples of the substituent that the alkoxy group of R ²⁰⁵ , R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ may have include, for example, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a formyl group, an acetyl group, C1-C20 carbonyl groups, such as a benzoyl group, a carbazoyl group, a phenylcarbonyl group, etc. are mentioned.

Furthermore, R ²⁰⁵ , R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ have a carbon number such as methyl group, ethyl group, propyl group, isopropyl group, cyclopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, etc. 1-4 alkyl groups or -NHCOR ²¹⁰ groups of acetylamino groups are preferred, and methyl groups or acetylamino groups are particularly preferred.
R ²¹⁰ has a hydrogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, or a substituent. The number of carbon atoms that may be present is 6 to 20 aryl groups.

The alkyl group of R ²¹⁰ is synonymous with the alkyl group exemplified for R ¹ in the general formula (I), and the substituent that may be present is also synonymous with the alkyl group exemplified for R ¹ in the general formula (I). is there.
The alkoxy group of R ²¹⁰ has the same meaning as the alkoxy group exemplified for R ²⁰⁵ , and the substituent that may be included is also the same. Among these, it is preferable that carbon number is 3 or more. Moreover, it is preferable that carbon number is 16 or less, and it is further more preferable that it is 12 or less. In addition, the aryl group of R ²¹⁰ has the same meaning as the aryl group exemplified for R ¹ in the general formula (I), and the substituent that may be included is the aryl group exemplified for R ¹ in the general formula (I). It is synonymous.

X ¹ represents a nitrogen atom or a methine group which may have a substituent. When X ¹ is a methine group, X ¹ may be unsubstituted or may have a substituent, but the substituent that X ¹ may have is the carbon number that may have a substituent. 1-10 alkyl groups, -COOR ^{211 and the} like. R ²¹¹ represents an alkyl group of carbon atoms, which may have a substituent 1 to 20.

X ¹ is preferably a nitrogen atom, a methine group, a methine group substituted with an alkyl group having 1 to 4 carbon atoms, or a methine group substituted with an alkoxycarbonyl group having 2 to 5 carbon atoms.
Among the compounds represented by the general formula (III), particularly preferable compounds include the compounds in Table 1 and Table 2 below. The present invention is not limited to these as long as the gist of the present invention is not exceeded.

The compound represented by the general formula (III) can be synthesized, for example, according to the method described in JP 2010-203335 A.
Examples of the heterocyclic compound include compounds represented by the following general formula (IV).

In general formula (IV),
R ³⁰¹ and R ³⁰² each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
D represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted alkoxy group having 1 to 10 carbon atoms, or a —NHCOR ³⁰⁵ group. Indicate
R ³⁰⁵ may have an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. An aryl group having 6 to 20 carbon atoms;
e represents an integer of 1 to 4, and when e is 2 or more, D present in 2 or more in one molecule may be the same or different,
R ³⁰³ has 1 to 1 carbon atoms which may have a hydrogen atom, a halogen atom, a cyano group, or a substituent.
10 represents an alkyl group, an aryl group having 6 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 10 carbon atoms which may have a substituent or a -COOR ³⁰⁶ group;
R ³⁰⁶ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent,
R ³⁰⁴ is an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, and an optionally substituted carbon number. An alkenyl group having 2 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms which may have a substituent, an alkoxycarbonyl group having 2 to 20 carbon atoms which may have a substituent, an aldehyde group, R ³⁰⁷ OOC (NC) C═CH— group, NC (NC) C═CH— group or a group represented by the following general formula (V):

R ³⁰⁷ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
D ′ is a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or -COOR represents ³⁰⁸ groups,
g represents an integer of 1 to 5, and when g is 2 or more, two or more D's in one molecule may be the same or different,
R ³⁰⁸ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent,
X ² represents a nitrogen atom or a methine group optionally having a halogen atom, a cyano group or —COOR ³⁰⁹ as a substituent,
R ³⁰⁹ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent.

R ³⁰¹ and R ³⁰² each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent.
The alkyl group that may have a substituent of R ³⁰¹ and R ³⁰² has the same meaning as the alkyl group exemplified for R ¹ in formula (I), and the substituent that the alkyl group may have also includes These are synonymous with the substituents and substituents that the alkyl group exemplified as R ¹ in formula (I) may have.
R ³⁰¹ and R ³⁰² preferably have 4 or more carbon atoms, and more preferably have 5 or more carbon atoms. Moreover, it is preferable that carbon number is 16 or less, and it is further more preferable that it is 12 or less. By not having too many carbon atoms, the molecular weight does not increase and the gram extinction coefficient may not be deteriorated.

Further, at least one of R ³⁰¹ and R ³⁰² is preferably a branched alkyl group, and at least one is preferably a branched alkyl group having 5 to 20 carbon atoms. Further, it is more preferable from the viewpoint of solubility that both of R ³⁰¹ and R ³⁰² are branched alkyl groups.
D represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted alkoxy group having 1 to 10 carbon atoms, or a —NHCOR ³⁰⁵ group. Indicates. Moreover, e shows the integer of 1-4 and when e is 2 or more, D which exists 2 or more in 1 molecule may be the same or different.

The alkyl group which may have a substituent of D is synonymous with the alkyl group having 1 to 10 carbon atoms exemplified by A ′ in the general formula (I), and the substituent which may have a general It is synonymous with the substituent illustrated with the alkyl group of A 'of a formula (I).
The alkoxy group which may have a substituent of D has the same meaning as the alkoxy group having 1 to 10 carbon atoms exemplified by A ′ in the general formula (I), and the substituent which may have a general It is synonymous with the substituent illustrated with the alkoxy group of A 'of a formula (I).

The alkyl group and alkoxy group of D preferably have 8 or less carbon atoms, and 6 or less carbon atoms are more preferable in terms of the Gram extinction coefficient.
R ³⁰⁵ may have an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. An aryl group having 6 to 20 carbon atoms is shown.

The alkyl group which may have a substituent of R ³⁰⁵ has the same meaning as the alkyl group exemplified as A ′ in formula (I), and the substituent which may have a substituent of formula (I) It is synonymous with the substituent illustrated by the alkyl group of A '. The alkyl group for R ³⁰⁵ preferably has 9 or less carbon atoms, and more preferably 8 or less.
The alkoxy group of R ^{305 is the same as} the alkoxy group exemplified as A ′ in the general formula (I), but also includes a phenoxy group, a naphthyloxy group, a dodecanoxy group, a toximethyl group, a methoxyethyl group, a methoxybutyl group, and an ethoxy group. Examples thereof include straight-chain, branched-chain, and cyclic alkoxy having 1 to 20 carbon atoms such as a methyl group, ethoxyethyl group, and ethoxybutyl group. Moreover, it is preferable that carbon number is 16 or less, and it is further more preferable that it is 12 or less. Specific examples of the substituent that the alkoxy group of R ³⁰⁵ may have include, for example, a halogen atom, an alkoxy group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms, a formyl group, an acetyl group, C1-C20 carbonyl groups, such as a benzoyl group, a carbazoyl group, a phenylcarbonyl group, etc. are mentioned.

Aryl groups R ³⁰⁵ are the same meaning as exemplified alkoxy group ^{R 1} of the general formula (I),
The substituent which may have is also synonymous with the substituent exemplified for the alkoxy group of R ^{1 in} formula (I). The aryl group for R ³⁰⁵ preferably has 10 or more carbon atoms, preferably 16 or less carbon atoms, and more preferably 12 or less carbon atoms.
If R ³⁰⁵ does not have too many carbon atoms, the molecular weight does not become too large, and the gram extinction coefficient may not deteriorate.

R ³⁰³ is a hydrogen atom, a halogen atom, a cyano group, an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted aryl group having 6 to 20 carbon atoms, or a substituent. An alkoxy group having 1 to 10 carbon atoms or a —COOR ³⁰⁶ group, which may have
The alkyl group and alkoxy group which may have a substituent of R ³⁰³ are synonymous with the alkyl group and alkoxy group exemplified as A ′ in formula (I), and the substituent which may have It is synonymous with the substituent illustrated by the alkyl group and alkoxy group of A 'of general formula (I), respectively.

The alkyl group and alkoxy group of R ³⁰³ preferably have 9 or less carbon atoms, and more preferably 8 or less.
Aryl group R ³⁰³ has the general formula has the same meaning as the aryl group exemplified for R ¹ of (I), it is preferable to have a substituent Among them is also a phenyl group.
R ³⁰⁶ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent. The alkyl group of R ³⁰⁶ has the same meaning as the alkyl group exemplified as A ′ in the general formula (I), and the substituent which may be included is also the substitution exemplified as the alkyl group as A ′ in the general formula (I). Synonymous with group. R ³⁰⁶ preferably has 8 or less carbon atoms, and more preferably 6 or less.

When R ³⁰³ and R ³⁰⁶ have not too many carbon atoms, the molecular weight does not become too large, and the gram extinction coefficient may not deteriorate.
R ³⁰⁴ is an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, and an optionally substituted carbon number. An alkenyl group having 2 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms which may have a substituent, an alkoxycarbonyl group having 2 to 20 carbon atoms which may have a substituent, an aldehyde group, R ³⁰⁷ OOC (NC) C═CH— group, NC (NC) C═CH— group or a group represented by the following general formula (V).

Examples of the alkyl group of R ³⁰⁴ include the same groups as those exemplified for R ¹ in formula (I), and the substituents that the alkyl group may have are also exemplified in R ¹ of formula (I). It is synonymous with the alkyl group. The alkyl group for R ³⁰⁴ preferably has 3 or more carbon atoms. The number of carbon atoms is preferably 18 or less, and more preferably 16 or less.
In the alkenyl group for R ³⁰⁴ , the position of the carbon-carbon unsaturated bond is not particularly limited, and may have a plurality of unsaturated bonds. Moreover, it may be linear or branched and may have an arbitrary substituent. Examples of the alkenyl group include a vinyl group, a propenyl group, and a hexenyl group, and among them, the number of carbon atoms is preferably 3 or more. Moreover, it is preferable that carbon number is 16 or less, and it is further more preferable that it is 12 or less.

As a specific example of the substituent that the alkenyl group of R ³⁰⁴ may have, a low-polarity substituent is preferable because of its solubility in a low-polarity solvent, an alkyl group having 1 to 20 carbon atoms, and a carbon number of 1 ˜20 alkoxy group, C2-C20 alkoxycarbonyl group, cyano group and the like.
Examples of the alkoxy group of R ³⁰⁴ include the same groups as those exemplified for R ³⁰⁵ in formula (IV), and among them, the number of carbon atoms is preferably 3 or more. Moreover, it is preferable that carbon number is 16 or less, and it is further more preferable that it is 12 or less.

Specific examples of the substituent that the alkoxy group of R ³⁰⁴ may have include, for example, a halogen atom, an alkoxy group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms, a formyl group, an acetyl group, C1-C20 carbonyl groups, such as a benzoyl group, a carbazoyl group, a phenylcarbonyl group, etc. are mentioned.
Examples of the alkyl group contained in the alkylcarbonyl group of R ³⁰⁴ include those having the same meaning as the alkyl group exemplified for R ¹ in formula (I), and preferably have 1 or more carbon atoms. The number of carbon atoms is preferably 18 or less, and more preferably 16 or less.

Examples of the alkoxy group contained in the alkoxycarbonyl group of R ³⁰⁴ include those having the same meaning as the alkoxy group exemplified for R ³⁰⁵ in formula (IV), and preferably have 1 or more carbon atoms. The number of carbon atoms is preferably 18 or less, and more preferably 16 or less.
Specific examples of the substituent that the alkylcarbonyl group of R ³⁰⁴ may have include an alkoxy group having 1 to 20 carbon atoms, and the substituent of the substituent that the alkoxycarbonyl group of R ³⁰⁴ may have. Specific examples include an alkyl group having 1 to 20 carbon atoms. When the carbon number of R ³⁰⁴ is in an appropriate range, the molecular weight does not become too large and the gram extinction coefficient may not deteriorate.

R ³⁰⁷ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent. Alkyl group R ³⁰⁷ may have include those alkyl groups as defined exemplified for R ¹ of the general formula (I), the substituent that may be alkyl groups have the R ^307, the general formula (I) It is synonymous with the substituent which the alkyl group illustrated by R < ¹ > of may have. R ³⁰⁷ preferably has 2 or more carbon atoms, more preferably 4 or more. Further, it is preferably 18 or less, and more preferably 16 or less. When the carbon number is in an appropriate range, the molecular weight does not become too large and the gram extinction coefficient may not deteriorate.

(D ′) D ′ of _g is a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or a carbon number which may have a substituent. 1 to 20 alkoxy groups or —COOR ³⁰⁸ groups are shown. G represents an integer of 1 to 5, and when g is 2 or more, two or more D's in one molecule may be the same or different.
Examples of the alkyl group for D ′ include the same groups as those exemplified for R ¹ in the general formula (I), and examples of the substituent that the alkyl group for D ′ may have include those represented by the general formula ( have alkyl groups exemplified for R ¹ of I) is synonymous with the substituent that may. The alkyl group for D ′ preferably has 3 or more carbon atoms. The number of carbon atoms is preferably 18 or less, and more preferably 16 or less.

Examples of the alkoxy group for D ′ include those having the same meaning as the alkoxy group exemplified for R ³⁰⁵ in formula (IV), and among these, the number of carbon atoms is preferably 4 or more, and more preferably 5 or more. preferable. Moreover, it is preferable that carbon number is 16 or less, and it is further more preferable that it is 12 or less.
Moreover, the substituent which the alkoxy group of D 'may have is synonymous with the substituent which the alkoxy group illustrated by ^R305 of general formula (IV) may have.

R ³⁰⁸ is an alkyl group of carbon atoms, which may have a substituent 1 to 10, are mentioned those exemplified alkyl groups as defined in A'of formula (I), also of R ³⁰⁸ The substituent that the alkyl group may have has the same meaning as the substituent that the alkyl group exemplified as A ′ in formula (I) may have. Among the alkyl groups R ^308, preferably a carbon number of 2 or more, preferably 8 or less, more preferably 6 or less.

When the number of carbon atoms of each group is in an appropriate range, the molecular weight does not become too large, and the gram extinction coefficient may not deteriorate.
X ² represents a nitrogen atom or a methine group optionally having a halogen atom, a cyano group or —COOR ³⁰⁹ as a substituent. R ³⁰⁹ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent.

The alkyl group which may have a substituent of R ^{309 and} the substituent which the alkyl group may have may have the alkyl group and the alkyl group exemplified in A ′ of the general formula (I). Examples thereof include those having the same meaning as a good substituent. Among them, the number of carbon atoms is preferably 8 or less, and more preferably 6 or less. When the number of carbon atoms in each group is not too large, the molecular weight does not become too large and the gram extinction coefficient may not deteriorate.

  Although the specific example of a compound represented by the said general formula (IV) is shown below, this invention is not limited to these, unless the meaning is exceeded.

The heterocyclic compound represented by the general formula (IV) can be synthesized, for example, according to the method described in JP-A-3-256793.
The heterocyclic compounds represented by the general formulas (II) to (IV) described above have a molecular weight of usually 2000 or less, including a substituent, when having a substituent, from the point of Gram extinction coefficient. Preferably it is 1000 or less, and is usually 300 or more, preferably 400 or more.

  Although there is no limitation in particular as an example of an anthraquinone type compound, the compound represented with the following general formula (VI) is preferable.

In general formula (VI), L is a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or an alkyl group having 1 to 20 carbon atoms which may have a substituent. An alkoxy group, an alkylsulfanyl group having 1 to 20 carbon atoms which may have a substituent, a cyano group, a hydroxy group, an amino group, a nitro group, a —COOR ⁴⁰¹ group, a —NHR ⁴⁰² group or a —NHCOR ⁴⁰³ group; T represents an integer of 1 to 4, and when t is 2 or more, L present in 2 or more in one molecule may be the same or different.

R ⁴⁰¹ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ⁴⁰² may have a substituent and may have a C 1-20 alkyl group, a substituent may have a C 1-20 alkoxy group, or a substituent. An aryl group having 6 to 20 carbon atoms;
R ⁴⁰³ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent.

L ′ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. An alkylsulfanyl group having 1 to 20 carbon atoms which may have a group, cyano group, hydroxy group, amino group, nitro group, -COOR ⁴⁰⁴ group, -NHR ⁴⁰⁵ group or -NHCOR ⁴⁰⁶ group, q is When integer of 1-4 is shown and q is 2 or more, L 'which exists 2 or more in 1 molecule may be the same or different.

R ⁴⁰⁴ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ⁴⁰⁵ may have an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. A good aryl group having 6 to 20 carbon atoms,
R ⁴⁰⁶ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent.

The alkyl group having 1 to 20 carbon atoms which may have a substituent of L and L ′ has the same meaning as the alkyl group exemplified for R ¹ in formula (I), and the alkyl groups of L and L are The substituent which may be present is also synonymous with the substituent which may be possessed by the alkyl group represented by R ^{1 in} the general formula (I).
The alkoxy group having 1 to 20 carbon atoms which may have a substituent of L and L ′ has the same meaning as the alkoxy group exemplified for R ³⁰⁵ in the general formula (IV), and the alkoxy group has The substituents that may be present are also synonymous.

Examples of the alkylsulfanyl group having 1 to 20 carbon atoms which may have a substituent of L and L ′ include a methylsulfanyl group, an ethylsulfanyl group, a propylsulfanyl group, an isopropylsulfanyl group, a butylsulfanyl group, and a hexylsulfanyl group. Cyclohexylsulfanyl group, octylsulfanyl group, 2-ethylhexylsulfanyl group and the like. Examples of the substituent that the alkylsulfanyl group may have include an alkoxy group having 1 to 20 carbon atoms, a carbonyl group having 1 to 20 carbon atoms, and a cyano group.

R ⁴⁰¹ and R ⁴⁰⁴ each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, and has the same meaning as the alkyl group exemplified for R ¹ in formula (I); The substituent which the alkyl group of R ⁴⁰¹ and R ⁴⁰⁴ may have is also synonymous with the substituent which the alkyl group of R ^{1 in} the general formula (I) may have.
R ⁴⁰² and R ⁴⁰⁵ are each independently an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. An aryl group having 6 to 20 carbon atoms which may have a group.

The alkyl group of R ⁴⁰² and ^{R 405,} have the same meanings as exemplified alkyl groups ^{R 1} of the general formula ^(I), which may substituent that the alkyl group have the ^{R 402} and ^{R 405,} the general formula have an alkyl group R ¹ of (I) is synonymous with the substituent that may. The alkoxy group of R ⁴⁰² and R ⁴⁰⁵ has the same meaning as the alkoxy group exemplified for R ³⁰⁵ in formula (IV), and the substituent that the alkoxy group may have is also synonymous.

The aryl group of R ⁴⁰² and ^{R 405,} have the same meanings as exemplified substituents ^{R 1} of the general formula ^(I), the substituent that may be an aryl group optionally having a ^{R 402} and ^{R 405} is generally It is synonymous with the substituent which the aryl group of R < ¹ > of Formula (I) may have.
R ⁴⁰³ and R ⁴⁰⁶ each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent.

The alkyl group of R ⁴⁰³ and ^{R 406,} have the same meanings as exemplified alkyl groups ^{R 1} of the general formula ^(I), which may substituent that the alkyl group have the ^{R 403} and ^{R 406,} the general formula have an alkyl group R ¹ of (I) is synonymous with the substituent that may.
Specific examples of the anthraquinone compound represented by the general formula (VI) are illustrated below, but the invention is not limited thereto as long as the gist thereof is not exceeded.

The anthraquinone compound represented by the general formula (VI) can be synthesized, for example, according to the methods described in US Pat. No. 5,558,808 and Japanese Patent Publication No. 11-506151.
From the point of Gram extinction coefficient, the anthraquinone compound represented by the general formula (VI) is
When it has a substituent, the molecular weight including the substituent is usually 2000 or less, preferably 1000 or less, and usually 300 or more, preferably 400 or more.

  About the density | concentration of the compound in the ink containing general formula (I)-(VI), it prepares by arbitrary density | concentrations according to the objective. When used as a compound for an electrowetting display, it is usually used at a concentration of 0.2% by mass or more, diluted in a solvent according to the required εC value, preferably 1% by mass or more, more preferably It is 5 mass% or more. The concentration is preferably higher, but is usually about 40% by mass or less.

When the ink of the present invention is used as black, it preferably contains at least one of the compounds of (II) to (VI) in addition to the above general formula (I). By including these compounds,
High light absorption can be realized in a wide wavelength range in the visible light region. Moreover, even when these compounds are used in combination, they are excellent in that they exhibit high solubility without lowering the solubility in a solvent.
Furthermore, the ink of the present invention may contain any additive suitable for each application as necessary, as long as the effects of the present invention are not impaired.

(Use)
The ink of the present invention is suitably used for a display. The display has a display part containing ink, a display that displays an image by controlling voltage application of the display part, a display that displays an image by changing a coloring state by voltage application, and electrophoresis in the display part It is particularly useful for displays that display using particles or aqueous media.

Here, the electrophoretic particles are charged particles, may have a color, and may include a plurality of types of electrophoretic particles in the display region. The aqueous medium is a fluid that may have a color, and may have a plurality of types of aqueous medium at the display site. Examples of the aqueous medium include water, non-charged liquid, liquid having affinity with water, and liquid having similar surface tension to water, such as alcohols such as diol and triol, alkali Examples thereof include liquids containing inorganic salts such as metal halides.

The benzothiazole compounds and inks of the present invention are particularly useful as inks used in electrowetting display or electrophoretic display.
Further, by combining the benzothiazole compound of the present invention with another compound, it is possible to provide a good black ink excellent in black hue, and it is also useful as a member that functions as an optical shutter.

The ink of the present invention can be used in any device as long as it has a display, but is particularly useful for electronic paper.
Examples of the display method include an electrowetting method and an electrophoresis method. Various uses of the display include those for computers, electronic paper, and electronic ink, and there is a possibility that most of the uses of the existing liquid crystal display can be replaced. The ink of the present invention is particularly preferable as an ink for an electrowetting display.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples.
<Method for measuring viscosity of solvent and ink>
The viscosity of the solvent and ink was measured using a viscometer VISCOMATE MODEL VM-10A manufactured by CAC MATERIALS CO. Ltd.

<Method of measuring relative permittivity of solvent and ink>
The measurement was performed by an impedance meter method using a Precision LCR meter 4284A manufactured by Agilent Technologies. After each solvent and ink were sandwiched between glass plates with ITO electrodes facing each other with an electrode spacing of 30 μm, the equivalent parallel capacitance was measured when a measurement frequency of 1 KHz and a test signal voltage of 0.1 V were applied. The relative dielectric constant was determined and evaluated.

Relative permittivity = equivalent parallel capacitance × electrode spacing / electrode area / vacuum permittivity (ε ₀ )
<Synthesis of Intermediate M-1>

20 g of 2-ethyl-1-hexanol, 21 ml of triethylamine and 100 ml of dichloromethane were mixed and cooled, and 25.5 g of 4-nitrobenzoyl chloride was added, followed by stirring at room temperature for 3 hours.
The reaction solution was extracted with hexane-water, and the obtained organic layer was concentrated and purified by silica gel column chromatography to obtain 37.8 g of an ester.
36.3 g of ester, 200 ml of methanol and 0.57 g of palladium-carbon were mixed, and a mixed solution of 15.5 g of hydrazine and 10 ml of methanol was added dropwise and stirred. The reaction solution was filtered and the filtrate was concentrated. The obtained solid was washed with water to obtain 31.4 g of an amine compound.

Amine 25.0 g, acetic acid 140 ml, sodium thiocyanate 33 g were mixed and cooled, and a mixed solution of bromine 17.6 g and acetic acid 20 ml was added dropwise and stirred. After filtering the reaction solution, the filtrate was extracted with ethyl acetate-water, and the resulting organic layer was concentrated to obtain 20 g of M-1 <Synthesis of Intermediate M-2>

M-2 was synthesized in the same manner as M-1, except that n-octanol was used instead of 2-ethyl-1-hexanol.
<Synthesis of Intermediate M-3>

M-3 was synthesized in the same manner as M-1, except that 2-ethyl-1-butanol was used instead of 2-ethyl-1-hexanol.
<Synthesis of Intermediate C-1>

A mixture of 5.0 g of 3-amino-4-methylacetanilide, 25 ml of N, N-dimethylformamide, 6.3 g of 1-bromo-2-ethylhexane and 5.3 g of potassium carbonate was stirred at 120 ° C. for 9 hours. After allowing to cool, the mixture was filtered, water was added to the filtrate, and the mixture was extracted with toluene.
The obtained organic layer was concentrated and purified by silica gel column chromatography to obtain 4.0 g of a monoalkyl compound.

Monoalkyl 3.8g, N-methylpyrrolidone 20ml, iodoethane 4.5g, potassium carbonate
3.0 g of the mixture was stirred at 70 ° C. for 8 hours. After cooling, the mixture was filtered, water was added to the filtrate, and the mixture was extracted with hexane.
The obtained organic layer was concentrated and then purified by silica gel column chromatography to obtain 3.3 g of C-1.
<Synthesis of Intermediate C-2>

A mixture of 3.5 g of 3-amino-4-methylacetanilide, 25 ml of N, N-dimethylformamide, 10.1 g of isobutyl iodide and 7.0 g of potassium carbonate was stirred at 120 ° C. for 24 hours. After allowing to cool, the mixture was filtered, water was added to the filtrate, and the mixture was extracted with toluene.
The obtained organic layer was concentrated and purified by silica gel column chromatography to obtain 2.7 g of C-2.
<Synthesis of Intermediate C-3>

C-3 was synthesized in the same manner as C-1, except that 3-aminoacetanilide was used instead of 3-amino-4-methylacetanilide.
<Synthesis of Intermediate C-4>

Similar to C-1, except that 3-methylaniline was used instead of 3-amino-4-methylacetanilide and 1-bromooctane was used instead of 1-bromo-2-ethylhexane,
C-4 was synthesized.
<Synthesis of Intermediate C-5>

C-5 was synthesized in the same manner as C-2 except that 3-methylaniline was used instead of 3-amino-4-methylacetanilide and 1-bromobutane was used instead of isobutyl iodide.
<Synthesis of Intermediate C-6>

C-6 was synthesized in the same manner as C-1, except that 3-amino-4-methylacetanilide was used as a raw material and isobutyl iodide was used instead of 1-bromo-2-ethylhexane.
<Synthesis of Intermediate C-7>

C- except that 3-methylaniline was used instead of 3-amino-4-methylacetanilide
In the same manner as in Example 2, C-7 was synthesized.
<Synthesis of Intermediate C-8>

Similar to C-2 except that 2,5-dimethoxyaniline was used instead of 3-amino-4-methylacetanilide and 1-bromobutane was used instead of isobutyl iodide.
Was synthesized.
<Synthesis of Intermediate C-9>

C-9 was synthesized in the same manner as C-2 except that 3-amino-4-methylacetanilide was used as a raw material and 1-bromohexane was used instead of isobutyl iodide.
<Synthesis of Intermediate C-10>

C--
10 was synthesized.
<Synthesis of Intermediate C-11>

C-11 was synthesized in the same manner as C-1, except that 3-amino-4-methoxyacetanilide was used instead of 3-amino-4-methylacetanilide.
<Synthesis of Intermediate C-12>

  C-12 was synthesized in the same manner as C-1, except that 2,5-dimethoxyaniline was used instead of 3-amino-4-methylacetanilide.

<Synthesis of Compound 1>

M-1 0.369 g, acetic acid 3 ml, propionic acid 1 ml, 44% nitrosylsulfuric acid 0.5 ml were mixed and stirred to form a diazo solution. In a separate container, 0.44 g of C-1, 10 ml of THF and an appropriate amount of sodium acetate were placed in an ice bath. The diazo solution was dropped into the solution for coupling. The reaction mixture was extracted with ethyl acetate-water, and the organic layer was concentrated and purified by silica gel column chromatography to obtain 0.19 g of compound 1.

<Synthesis of Compound 2>
Compound 2 was synthesized in the same manner as Compound 1, except that 2-amino-6-thiocyanobenzothiazole was used instead of M-1 and C-7 was used instead of C-1.

<Synthesis of Compound 3>
2-amino-6-chlorobenzothiazole is used in place of M-1 and C-
Compound 3 was synthesized in the same manner as the synthesis of Compound 1, except that 3 was used.

<Synthesis of Compound 4>
Compound 4 was synthesized in the same manner as in the synthesis of Compound 1, except that C-3 was used instead of C-1.

<Synthesis of Compound 5>
2-amino-6-chlorobenzothiazole is used in place of M-1 and C-
Compound 5 was synthesized in the same manner as in the synthesis of Compound 1, except that 4 was used.

<Synthesis of Compound 6>
Compound 6 was synthesized in the same manner as in the synthesis of Compound 1, except that C-5 was used instead of C-1.

<Synthesis of Compound 7>
Compound 7 was synthesized in the same manner as in the synthesis of Compound 1, except that C-6 was used instead of C-1.

<Synthesis of Compound 8>
Compound 8 was synthesized in the same manner as in the synthesis of Compound 1, except that C-2 was used instead of C-1.

<Synthesis of Compound 9>
2-amino-6-octylbenzothiazole is used instead of M-1, and C is used instead of C-1.
Compound 9 was synthesized in the same manner as in the synthesis of Compound 1, except that -8 was used.

<Synthesis of Compound 10>
Compound 10 was synthesized in the same manner as in the synthesis of Compound 1, except that C-9 was used instead of C-1.

<Synthesis of Compound 11>
Compound 11 was synthesized in the same manner as in the synthesis of Compound 1, except that M-2 was used instead of M-1.

<Synthesis of Compound 12>
2-amino-6-octylbenzothiazole is used instead of M-1, and C is used instead of C-1.
Compound 12 was synthesized in the same manner as in the synthesis of Compound 1, except that -10 was used.

<Synthesis of Compound 13>
Compound 13 was synthesized in the same manner as the synthesis of Compound 1, except that M-3 was used instead of M-1 and C-5 was used instead of C-1.

<Synthesis of Compound 14>
Compound 14 was synthesized in the same manner as in the synthesis of Compound 1, except that M-3 was used instead of M-1.

<Synthesis of Compound 15>
Compound 15 was synthesized in the same manner as the synthesis of Compound 1 except that M-3 was used instead of M-1 and C-7 was used instead of C-1.

<Synthesis of Compound 16>
2-amino-6-chlorobenzothiazole is used in place of M-1 and C-
Compound 16 was synthesized in the same manner as in the synthesis of Compound 1, except that 11 was used.

<Synthesis of Compound 17>
2-amino-6-chlorobenzothiazole is used in place of M-1 and C-
Compound 17 was synthesized in the same manner as in the synthesis of Compound 1, except that 12 was used.
[Comparative Example 1]
<Synthesis of Comparative Example Compound 1>
Compound M-2 of JP-A-01-136787 was synthesized as Comparative Example Compound 1.

  Each compound synthesized in Examples 1 to 17 and Comparative Example 1 is shown below.

<Test results>
Compounds 1 to 17 and Comparative Example Compound 1 were subjected to a solubility test using n-decane (relative dielectric constant: 2.04, boiling point: 174 ° C.) as an ink solvent. In addition, Table 3 summarizes the test results of the solution color, absorption maximum wavelength (λmax), solubility, and εC.
<Measurement Method of Absorption Maximum Wavelength (λmax)> Compounds 1 to 17 and Comparative Example Compound 1 were weighed, and a solution diluted with n-decane using a 100 ml volumetric flask was placed in a quartz cell, and Hitachi spectrophotometer U-4100 was used. The spectrum was measured at.
The value of λmax was read from the obtained spectrum.

<Solubility test>
The solubility of each compound in n-decane was measured as follows. Each compound was added to n-decane until dissolved residue was generated, and sonicated at 30 degrees for 30 minutes. After leaving 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, the solubility of each compound is calculated from the relationship with the extinction coefficient measured in advance, and the molar extinction coefficient ε (Lmol ⁻¹ cm ⁻¹ ) and the saturated solution concentration C ( The value of product εC of molL ⁻¹ ) was determined.

The ink and benzothiazole compound of the present invention can be suitably used for displays and optical shutters, and can be particularly suitably used, for example, as electrowetting displays such as electronic paper and electrophoretic displays.

Claims (12)

An ink comprising a solvent having a relative dielectric constant of 2.2 or less at a measurement frequency of 1 KHz and a boiling point of 115 ° C. or more, and a benzothiazole compound, wherein the benzothiazole compound is represented by the following general formula (I) :

[In general formula (I),
R ¹ and R ² each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent or an aryl group having 6 to 20 carbon atoms which may have a substituent,
A represents a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or a —COOR ³ group;
R ³ represents an alkyl group having 1 to 20 carbon atoms,
m represents an integer of 0 to 4, and when m is 2 or more, two or more A in one molecule may be the same or different,
A ′ represents an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted alkoxy group having 1 to 10 carbon atoms, or —NHCOR ⁴ group;
R ⁴ represents an alkyl group having 1 to 10 carbon atoms,
n represents an integer of 0 to 4, and when n is 2 or more, A ′ present in 2 or more in one molecule may be the same or different.
Ink represented by The ink according to claim 1, wherein the solvent contains at least one linear or branched aliphatic hydrocarbon solvent . When the benzothiazole compound is dissolved in n-decane, the absorption maximum wavelength in the 350 to 750 nm wavelength region is in the range of 450 to 600 nm, and the molar extinction coefficient ε (Lmol ^{−1 at the} absorption maximum wavelength). cm ^-1) and room temperature (25 ° C.) in the ink according to claim 1 or 2 product εC is a compound showing a 500 cm ^-1 or more values of the concentration of a saturated solution of the same solvent C (molL ^-1).   The ink according to any one of claims 1 to 3, further comprising at least one selected from the group consisting of a heterocyclic compound and an anthraquinone compound. The ink according to claim 4, wherein the heterocyclic compound contains at least one of the following general formulas (II), (III), and (IV).

[In the general formula (II),
R ¹⁰¹ represents an alkyl group having 2 to 10 carbon atoms which may have a substituent,
R ¹⁰² represents an alkyl group having 3 to 10 carbon atoms which may have a substituent,
The phenylene group and the phenyl group may have a substituent. ]

[In general formula (III),
R ²⁰¹ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ²⁰² represents a cyano group or a —COOR ²⁰⁹ group,
R ²⁰⁹ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ²⁰³ and R ²⁰⁴ each independently represent an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ²⁰⁵ , R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ each independently have a hydrogen atom, a halogen atom, a substituent, or an alkyl group having 1 to 20 carbon atoms or a substituent. An alkoxy group having 1 to 20 carbon atoms or a —NHCOR ²¹⁰ group;
R ²¹⁰ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms,
X ¹ represents a nitrogen atom or a methine group which may have a substituent,
R ²⁰³ and R ²⁰⁴ may be bonded to each other to form a ring structure.

[In general formula (IV),
R ³⁰¹ and R ³⁰² each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
D represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted alkoxy group having 1 to 10 carbon atoms, or a —NHCOR ³⁰⁵ group. Indicate
R ³⁰⁵ may have an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. An aryl group having 6 to 20 carbon atoms;
e represents an integer of 1 to 4, and when e is 2 or more, D present in 2 or more in one molecule may be the same or different,
R ³⁰³ has 1 to 1 carbon atoms which may have a hydrogen atom, a halogen atom, a cyano group, or a substituent.
10 represents an alkyl group, an aryl group having 6 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 10 carbon atoms which may have a substituent or a -COOR ³⁰⁶ group;
R ³⁰⁶ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent,
R ³⁰⁴ is an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, and an optionally substituted carbon number. An alkenyl group having 2 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms which may have a substituent, an alkoxycarbonyl group having 2 to 20 carbon atoms which may have a substituent, an aldehyde group, R ³⁰⁷ OOC (NC) C═CH— group, NC (NC) C═CH— group or a group represented by the following general formula (V):

R ³⁰⁷ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
D ′ is a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or -COOR represents ³⁰⁸ groups,
g represents an integer of 1 to 5, and when g is 2 or more, two or more D's in one molecule may be the same or different,
R ³⁰⁸ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent,
X ² represents a nitrogen atom or a methine group optionally having a halogen atom, a cyano group or —COOR ³⁰⁹ as a substituent,
R ³⁰⁹ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent. The said anthraquinone type compound is a compound represented by the following general formula (IV).
Or the ink according to 5.

[In general formula (VI),
L has a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, and a substituent. An alkylsulfanyl group having 1 to 20 carbon atoms, cyano group, hydroxy group, amino group, nitro group, —COOR ⁴⁰¹ group, —NHR ⁴⁰² group or —NHCOR ⁴⁰³ group, which may have
R ⁴⁰¹ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ⁴⁰² may have a substituent and may have a C 1-20 alkyl group, a substituent may have a C 1-20 alkoxy group, or a substituent. An aryl group having 6 to 20 carbon atoms;
R ⁴⁰³ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
t represents an integer of 1 to 4, and when t is 2 or more, L present in 2 or more in one molecule may be the same or different,
L ′ represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. An alkylsulfanyl group having 1 to 20 carbon atoms which may have, a cyano group, a hydroxy group, an amino group,
A nitro group, -COOR ⁴⁰⁴ group, -NHR ⁴⁰⁵ group or -NHCOR ⁴⁰⁶ group,
R ⁴⁰⁴ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
R ⁴⁰⁵ may have an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or a substituent. A good aryl group having 6 to 20 carbon atoms,
R ⁴⁰⁶ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent,
q represents an integer of 1 to 4, and when q is 2 or more, L ′ present in 2 or more in one molecule may be the same or different. ] The ink according to any one of claims 1 to 6 , which is used for a display or an optical shutter. A display portion including an ink according to any one of claims 1 to 7 for displaying an image by controlling the voltage application of the display region display. The display according to claim 8 , wherein the display portion contains electrophoretic particles or an aqueous medium. The display according to claim 8 or 9 , wherein an image is displayed by changing a coloring state by applying a voltage. The display according to any one of claims 8 to 10 , wherein an image is displayed by an electrowetting method or an electrophoresis method. The electronic paper which has a display of any one of Claims 8-11 .