Ink containing heterocyclic azo dye, and dye for use in said ink
View Patent ↗The invention relates to an ink which comprises: a low-polarity solvent having a relative permittivity of 3 or less at a measuring frequency of 1 kHz; and a specific heterocyclic azo dye.
1. An ink which comprises: a low-polarity solvent having a relative permittivity, as measured at a frequency of 1 kHz, of 3 or less; and a heterocyclic azo dye, wherein the heterocyclic azo dye is a dye represented by the following general formula (I):
wherein
R 1 represents a hydrogen atom or an optionally substituted alkyl group having 1-20 carbon atoms,
R 2 represents a cyano group or a COOR 5 group,
R 5 represents an optionally substituted alkyl group having 1-20 carbon atoms,
R 3 and R 4 each independently represent an optionally substituted alkyl group having 5-20 carbon atoms,
A represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1-20 carbon atoms, an optionally substituted alkoxy group having 1-20 carbon atoms, or an NHCOR 6 group,
n represents an integer of 1-4, and when n is 2 or larger, the A's may be the same or different,
R 6 represents a hydrogen atom, an alkyl group having 1-20 carbon atoms, an alkoxy group having 1-20 carbon atoms, or an aryl group,
X represents a nitrogen atom or a methine group optionally substituted with a substituent selected from the group consisting of an optionally substituted alkyl group having 1-10 carbon atoms, a COOR 7 group, and cyano, wherein R 7 represents an optionally substituted alkyl group having 1-20 carbon atoms, and
R 3 and R 4 may be bonded to each other to form a cyclic structure.
2. The ink according to claim 1 , wherein the low-polarity solvent comprises at least one member selected from the group consisting of hydrocarbon solvents, silicone oils, and fluorocarbon solvents.
3. The ink according to claim 1 , wherein the heterocyclic azo dye is a dye in which, when dissolving the dye in n-decane, an absorption-maximum wavelength in the wavelength range of 350-750 nm is in the range of 450-600 nm, and the product of a molar extinction coefficient ε (Lmol −1 cm −1 ) at the absorption-maximum wavelength and a concentration C (molL −1 ) of saturated solution in the solvent at room temperature (25° C.), εC, has a value of 500 cm −1 or larger.
4. The ink according to claim 1 , which further comprises at least one of a pyrazole dye and an alkylamine-substituted anthraquinone dye.
5. The ink according to claim 4 , wherein the pyrazole dye is represented by the following general formula (II) and the alkylamine-substituted anthraquinone dye is represented by the following general formula (III):
wherein R 9 represents an alkyl group having 2-10 carbon atoms, and R 10 represents an alkyl group having 3-10 carbon atoms, and the phenyl group and the phenylene group each may independently have a substituent;
wherein Y represents a hydrogen atom or a COOR 13 group, and R 11 to R 13 each independently represent an optionally substituted alkyl group having 1-20 carbon atoms, at least one of R 11 to R 13 is an optionally substituted branched alkyl group having 4-20 carbon atoms, and the anthraquinone ring may have any substituent other than the Y, NHR 11 and NHR 12 .
6. A display or optical shutter comprising the ink according to claim 1 .
7. A display which comprises a display part containing the ink according to claim 1 , in which an image is displayed by controlling voltage application to the display part.
8. The display according to claim 7 , wherein the display part contains electrophoretic particles or an aqueous medium.
9. The display according to claim 7 , wherein an image is displayed by changing the coloration by means of voltage application.
10. The display according to claim 7 , wherein an image is displayed by an electrowetting system or an electrophoretic system.
11. An electronic paper which comprises the display according to claim 7 .
12. A heterocyclic azo dye represented by the following general formula (IV):
wherein
R 1 represents a hydrogen atom or an optionally substituted alkyl group having 1-20 carbon atoms,
R 2 represents a cyano group or a COOR 5 group,
R 5 represents an optionally substituted alkyl group having 1-20 carbon atoms,
R 101 and R 102 each independently represent an optionally substituted alkyl group having 5-20 carbon atoms,
A represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1-20 carbon atoms, an optionally substituted alkoxy group having 1-20 carbon atoms, or an NHCOR 6 group,
n represents an integer of 1-4, and when n is 2 or larger, the A's may be the same or different,
R 6 represents a hydrogen atom, an alkyl group having 1-20 carbon atoms, an alkoxy group having 1-20 carbon atoms, or an aryl group,
X represents a nitrogen atom or a methine group optionally substituted with a substituent selected from the group consisting of an optionally substituted alkyl group having 1-10 carbon atoms, a COOR 7 group, and cyano, wherein R 7 represents an optionally substituted alkyl group having 1-20 carbon atoms, and
R 101 and R 102 may be bonded to each other to form a cyclic structure.
13. The ink according to claim 1 , wherein X represents a nitrogen atom.
14. The ink according to claim 1 , wherein X represents an optionally substituted methine group.
15. The ink according to claim 1 , wherein R 2 represents a cyano group.
16. The ink according to claim 1 , wherein R 2 represents a COOR 5 group.
17. The ink according to claim 1 , wherein at least one A represents a halogen atom, an optionally substituted alkyl group having 1-20 carbon atoms, an optionally substituted alkoxy group having 1-20 carbon atoms, or an NHCOR 6 group.
18. An ink which comprises: a low-polarity solvent having a relative permittivity, as measured at a frequency of 1 kHz, of 3 or less; and a heterocyclic azo dye, wherein the heterocyclic azo dye is a dye represented by the following general formula (I):
wherein
R 1 represents a hydrogen atom or an optionally substituted alkyl group having 1-20 carbon atoms,
R 2 represents a cyano group or a COOR 5 group,
R 5 represents an optionally substituted alkyl group having 1-20 carbon atoms,
R 3 and R 4 each independently represent an optionally substituted alkyl group having 4-20 carbon atoms in which at least one of R 3 and R 4 is branched,
A represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1-20 carbon atoms, an optionally substituted alkoxy group having 1-20 carbon atoms, or an NHCOR 6 group,
n represents an integer of 1-4, and when n is 2 or larger, the A's may be the same or different,
R 6 represents a hydrogen atom, an alkyl group having 1-20 carbon atoms, an alkoxy group having 1-20 carbon atoms, or an aryl group,
X represents a nitrogen atom or a methine group optionally substituted with a substituent selected from the group consisting of an optionally substituted alkyl group having 1-10 carbon atoms, a COOR 7 group, and cyano, wherein R 7 represents an optionally substituted alkyl group having 1-20 carbon atoms, and
R 3 and R 4 may be bonded to each other to form a cyclic structure.