Pyrazole disazo dye and ink containing the dye
View Patent ↗The invention provides a specific pyrazole disazo dye which is a yellow dye having excellent solubility in nonpolar solvents, in particular, hydrocarbon solvents, and having a high extinction coefficient. The dye preferably is preferably a pyrazole disazo dye represented by the following general formula (I): (wherein R 1 represents a C 2 -C 10 alkyl group; R 2 represents a C 3 -C 10 alkyl group; the six-membered ring A represents a phenyl group which may have a substituent; and the six-membered ring B represents a phenylene group which may have a substituent).
1. A pyrazole disazo dye having a solubility in n-decane of 1% by weight or higher at 25° C. and ordinary pressure, which is represented by the following formula (I):
in which R 1 represents a C 2 -C 10 alkyl group; R 2 represents a C 3 -C 10 alkyl group; the six-membered ring A represents a phenyl group which may have a substituent; and the six-membered ring B represents a phenylene group which may have a substituent.
2. The pyrazole disazo dye according to claim 1 , wherein R 2 is a branched alkyl.
3. The pyrazole disazo dye according to claim 1 , wherein the six-membered ring A is a phenyl group which may be substituted with at least one group selected from the group consisting of C 1 -C 10 alkyl groups and C 1 -C 10 alkoxy groups, and the six-membered ring B is a phenylene group which may be substituted with at least one group selected from the group consisting of C 1 -C 10 alkyl groups and C 1 -C 10 alkoxy groups.
4. The pyrazole disazo dye according to claim 1 , wherein the six-membered ring B is a 1,4-phenylene group.
5. A pyrazole disazo dye wherein the product of a molar extinction coefficient (Lmol −1 cm −1 ) of an n-decane solution thereof at an absorption maximum wavelength in the range of 350-800 nm and a concentration (molL −1 ) of a saturated solution thereof in the solvent at 25° C. and ordinary pressure, is 2,000 (cm −1 ) or larger, which is represented by the following formula (I):
in which R 1 represents a C 2 -C 10 alkyl group; R 2 represents a C 3 -C 10 alkyl group; the six-membered ring A represents a phenyl group which may have a substituent; and the six-membered ring B represents a phenylene group which may have a substituent.
6. An ink comprising the pyrazole disazo dye according to claim 1 .
7. An ink comprising the pyrazole disazo dye according to claim 5 .
8. The pyrazole disazo dye according to claim 1 , wherein R 1 represents a C 2 -C 6 alkyl group.
9. The pyrazole disazo dye according to claim 8 , wherein R 1 represents propyl, butyl, pentyl or hexyl.
10. The pyrazole disazo dye according to claim 1 , wherein R 2 represents a C 3 -C 6 alkyl group.
11. The pyrazole disazo dye according to claim 2 , wherein R 2 represents a tert-butyl group.
12. The pyrazole disazo dye according to claim 1 , wherein ring A is unsubstituted.
13. The pyrazole disazo dye according to claim 1 , wherein ring A is substituted with a C 3 -C 8 linear alkyl group.
14. The pyrazole disazo dye according to claim 1 , wherein the solubility is 3% by weight or higher at 25° C.
15. The pyrazole disazo dye according to claim 1 , wherein the solubility is 5% by weight or higher at 25° C.
16. The pyrazole disazo dye according to claim 1 , wherein a solution thereof in a nonpolar solvent has an absorption maximum wavelength of about 350-500 nm in a wavelength range of 350-800 nm.
17. The pyrazole disazo dye according to claim 16 , wherein the solution has no other absorption maximum in the wavelength range of 350-800 nm.