Azo dyes and their preparation and use

Details Azo dyes and their preparation and use Azo dyes and their preparation and use

2001-05-29

2003-05-13

Klemanski, Helene (Department: 1755)

Compositions: coating or plastic

Coating or plastic compositions

Marking

C534S862000, C008S437000, C008S641000, C008S673000, C008S917000, C008S918000, C008S919000

Reexamination Certificate

active

06562115

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to novel monoazo dyes and their salts, a method of their preparation and their use in dying and printing operations. It relates also to liquid dye preparations containing these dyes, particularly to aqueous inks for ink jet printing.
BACKGROUND OF THE INVENTION
Ink jet printing processes are essentially of two types: In continuous stream ink jet printing systems, ink is emitted in a continuous stream under pressure through a nozzle. The stream breaks up into droplets at a certain distance from the nozzle. If a specific location on the recording sheet has to be printed the individual droplets are directed to the recording sheet, otherwise they are directed to a gutter. This is done for example by charging unnecessary droplets in accordance with digital data signals and passing them through an electric static field which adjusts the trajectory of these droplets in order to direct them to the gutter. The inverse procedure may also be used wherein uncharged droplets are directed to the gutter.
In the non-continuous process, or the so-called “drop-on-demand” systems, a droplet is generated in accordance with digital data signals only if it is to be placed onto the recording sheet.
In the classical ink jet printing process the traditional four-color system YMCK is used, wherein a yellow, a magenta, a cyan and a black ink are printed onto the recording sheet. In order to improve color rendering, further inks containing for example orange, red, blue, or green dyes are used. Such dyes are called “spot dyes”. In the classical ink jet printing process, spot dyes may be generated only by mixing of the corresponding primary colors. Spot colors generated in this way (mixed colors) are rather dull and not very brilliant. Therefore, there is a need for new, brilliant red dyes with excellent light stability and high solubility in the aqueous ink medium for the new, multicolor ink systems.
Although a number of red dyes have been proposed as dyes for ink jet printing, none meets all the necessary requirements.
The dye of formula (I) (Acid Red 37) having a red hue is described in patent application EP 0,953,613.
This dye shows the wanted hue, but its solubility is not sufficient.
The dye of formula (II) having a magenta hue is described in patent application WO 96-24,636 (Example 102).
This dye shows high solubility, but it is too dull and too bluish.
These two dyes, representing the state of the art, do not satisfy all the required demands for spot dyes when used in red recording liquids for ink jet printing. Neither do they satisfy all the required demands if they are used in the formulation of inks for ink jet printing that should provide brilliant images or colorings with excellent color rendition (extended gamut) on any type of recording medium as plain or coated paper, coated or uncoated, opaque or transparent synthetic materials, because these dyes are either not soluble enough or show a too bluish red.
Dyes used for such recording liquids have to show a good solubility in the essentially aqueous ink liquid; they have to penetrate into the recording medium and should not show dye aggregation on the surface of the recording medium (“bronzing”). They need to provide printed images having high optical density, good water fastness, and good light stability. They need to be stable in the ink even when the recording liquid is stored for a long time under adverse conditions. Various types of compositions have been proposed as inks for ink jet printing. Typical inks comprise one or more dyes, water, organic cosolvents and other additives.
The inks have to meet the following criteria:
(1) The ink gives images of excellent quality on any type of recording medium.
(2) The ink gives printed images exhibiting good water fastness.
(3) The ink gives printed images exhibiting good light stability.
(4) The ink gives printed images exhibiting excellent smudge behavior.
(5) The ink does not clog jetting nozzles of the ink jet printers even when these are kept uncapped while recording is suspended for long periods.
(6) The ink may be stored for long periods of time without deterioration of its quality.
(7) The values of the physical properties of the inks, such as viscosity, conductivity and surface tension are all within defined ranges well suited for the intended use.
(8) The ink has to be non-toxic, not flammable and safe.
SUMMARY OF THE INVENTION
Accordingly, an object of the invention is to provide novel monoazo dyes, of the general formulas (III) and (IV), and processes for their preparation. These dyes show a red hue and, at the same time, excellent light stability and high solubility. They provide images or colorings showing good overall properties, in particular in the ink jet printing process, where they provide images with maximum color rendition, especially in six-color printing.
Another object of the invention is the provision of liquid dye preparations, especially of recording liquids for ink jet printing, showing a spectrally unchanged hue on any type of recording medium as plain or coated paper, coated or uncoated, opaque or transparent synthetic materials.
A further object of the present invention is to provide recording liquids satisfying also all the other requirements mentioned above.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to novel monoazo dyes of general formulas (III)
wherein
R
1
, R
2
independently represent hydrogen, alkyl or alkoxy each having 1 to 4 C atoms, fluoro, chloro or bromo;
R
3
represents hydrogen, alkyl with 1 to 6 C atoms, substituted alkyl with 2 to 6 C atoms, wherein the substituents are selected from the group consisting of cyano, carboxy, hydroxy, carboxymethyl and carboxyethyl, or phenyl or phenyl substituted by methyl, chloro, bromo, carboxy or sulfo;
D
1
represents unsubstituted or substituted alkylene with 2 or 3 C atoms, wherein the substituents are selected from the group consisting of alkyl or alkenyl with 1 to 6 C atoms, fluoro, chloro and bromo; CH
2
OCH
2
or CH═CH or where D
1
is part of an aliphatic ring consisting of 5 or 6 C atoms; and
M represents hydrogen, a metal cation or an ammonium cation, which may be substituted by one or more alkyl or substituted alkyl groups each having from 1 to 18 C atoms.
Preferred are monoazo dyes of formulas (III) and (IV), wherein M is as described above; and
R
1
, R
2
independently represent hydrogen, methyl, methoxy or chloro;
R
3
represents hydrogen, alkyl with 1 to 6 C atoms, substituted alkyl with 2 or 3 C atoms, wherein the substituents are selected from the group consisting of cyano, carboxy and hydroxy; and
D
1
represents n-alkylene with 2 or 3 C atoms, CH
2
OCH
2
or CH═CH.
Also preferred are monoazo dyes of formulas (III) and (IV), wherein M, R
1
, R
2
and D
1
are as described above; and
R
3
represents hydrogen, methyl, CH
2
CH
2
COOH or CH
2
CH
2
OH.
Especially preferred are monoazo dyes of formulas (III) and (IV), wherein M, R
1
, R
2
und D
1
are as described above; and
R
3
represents hydrogen.
Also preferred are monoazo dyes of general formula (IV), wherein M is as described above; and
R
2
represents hydrogen, methyl, methoxy or chloro;
R
3
represents hydrogen, alkyl with 1 to 6 C atoms, substituted alkyl with 2 to 6 C atoms, wherein the substituents are selected from the group consisting of cyano, carboxy, hydroxy, carboxymethyl and carboxyethyl; or phenyl or phenyl substituted by methyl, chloro, bromo, carboxy or sulfo; and
D
1
represents unsubstituted or substituted alkylene with 2 or 3 C atoms, wherein the substituents are selected from the group consisting of alkyl or alkenyl with 1 to 6 C atoms, fluoro, chloro and bromo; CH
2
OCH
2
or where D
1
is part of an aliphatic ring consisting of 5 or 6 C atoms.
The prepared dyes of general formula (III) are listed in Table 1 together with the position of their absorption maximum in aqueous solution:
TABLE 1
Com-
pound
&lgr;
max
(nm) in
No.
R
1
R
3
D
1
M
H
2
O
100
H
H
(CH
2
)
2
Na
512
101
H
H
(CH
2
)
3
Na
512
102
CH
3
H
(CH
2
)
2
Na
509
103
CH
3
H
(CH
2
)
3
N

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