Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
1999-12-23
2001-06-26
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031480, C106S031500, C008S639000, C008S641000
Reexamination Certificate
active
06251174
ABSTRACT:
This invention relates to a composition comprising two or more dyes, to inks containing such compositions and to processes using said inks in printing and imaging technologies, especially ink jet printing.
Ink jet printing is a non-impact printing technique which involves ejecting, thermally or by action of an oscillating piezo crystal, droplets of ink continuously or on demand from a fine nozzle directly onto a substrate such as paper, plastics, textile, metal or glass. The inks used in an ink jet printer are required to meet a number of criteria. For example, they preferably provide sharp, non-feathered images which have good water fastness, light fastness and optical density. Furthermore, the inks desirably dry quickly when applied to a substrate, however, they should not dry or crust over in the ink jet head as this can result in clogging of the ink jet nozzle. The inks are desirably storage stable over long periods of time without deterioration in the properties of the ink.
We have found that mixtures of certain dyes are valuable as colorants for ink jet printing inks. In particular we have surprisingly found that when the mixture of dyes is incorporated into an ink, the mixture shows a synergistic effect compared to the individual components providing improvements in solubility, operability and, particularly, in print optical density. Furthermore, inks incorporating the dye mixtures exhibit a rapid fixation on paper and give a black print on plain paper which exhibits little or no bronzing and a high water fastness.
According to a first aspect of the present invention, there is provided a composition comprising:
(i) a dye of Formula (1) or a salt thereof:
wherein n is 0 or 1; and
(ii) at least one dye selected from a dye of the Formula (2), (3), (4), (5), (6), (7) and salts thereof:
wherein:
R
1
is vinyl sulphonyl, hydroxyethyl sulphonyl or a group which is convertible to vinyl sulphonyl when treated with aqueous alkali.
Preferably n has a value of 0.
The composition preferably comprises:
(a) from 99.9 to 0.1 parts, more preferably from 70 to 10 parts of a dye of Formula (1); and
(b) from to 0.1 to 99.9 parts, more preferably from 30 to 90 parts in total of one or more dye(s) selected from the dyes of Formula (2), (3), (4), (5), (6) and (7);
wherein the parts are by weight and the sum of the parts (a) and (b)=100.
As will be understood, the composition may in addition to a dye of Formula (1) contain a single dye selected from the dyes of Formulae (2) to (7), or a mixture of two or more of the dyes of Formulae (2) to (7).
A preferred mixture of dyes of Formulae (2) to (7) comprises a mixture of the dyes of Formula (4), (5) and (6), more preferably a mixture comprising from 20 to 80 parts of the dye of Formula (4), from 20 to 80 parts of the dye of Formula (5) and from 20 to 80 parts of the dye of Formula (6), wherein the parts are by weight and the sum of the parts of the dyes of Formula (4), (5) and (6)=100. An especially preferred mixture of dyes of Formulae (2) to (6) comprises an approximately 1:1:1 mixture, by weight, of dyes of the Formula (4), (5) and (6).
When R
1
in the dye of Formula (7) is a group which is convertible to a vinyl sulphonyl group when treated with aqueous alkali it is preferably of the formula —SO
2
CH
2
CH
2
OSO
3
H, —SO
2
CH
2
CH
2
SSO
3
H, —SO
2
CH
2
CH
2
Cl or —SO
2
CH
2
OCOCH
3
. More preferably R
1
is —SO
2
CH
2
CH
2
OH or, especially, —SO
2
CH
2
CH
2
OSO
3
H
Preferably R
1
is attached in the para position relative to the azo group in the dye of Formula (7).
A preferred composition according to the first aspect of the present invention comprises from 90 to 10 parts of a dye of Formula (1); and from 10 to 90 parts of a dye of Formula (2); wherein the parts are by weight and the sum of the parts of the dye of Formula (1) and the dye of Formula (2)=100.
The dye of Formula (1) may be prepared using methods known in the art for the preparation of similar azo compounds. For example, a suitable method for the preparation of the dye of Formula (1) in the form of its sodium salt is disclosed in Example 2 of EP 0 356 080. The dye of Formula (1) may be converted into the free acid form or into a salt with a counter ion other than sodium by using well known techniques. For example, the alkali metal salts of the dye of Formula (1) may be converted into a salt with ammonia or an amine by dissolving the dye in the form of a salt with an alkali metal, acidifying with a mineral acid and adjusting the pH of the solution to pH 9 to 9.5 with ammonia or the amine and removing the alkali metal cations by dialysis. An example of a suitable process for converting the sodium salt of the dye of Formula (1) to the ammonium salt is an analogous one to that described in Example 21 of EP 0 356 080.
The dye of Formula (2) is Food Black 2 and is commercially available from Bayer.
The dye of Formula (3) is commercially available as Colour Index Direct Black 19. The dye of Formula (3) may be prepared using conventional techniques for the preparation of azo dyes. For example a suitable method comprises:
(1) diazotising 1,4-phenylenediamine using, for example, sodium nitrite in a mineral acid at 0 to 5° C.;
(2) coupling 8-amino-1-naphthol-3,6-disulphonic acid with an approximately equimolar quantity of the diazotised 1,4-phenylene diamine from stage (1) under slightly acidic conditions;
(3) adjusting the pH of the solution resulting from stage (2) so that it is alkaline, preferably in the range pH 8 to 9, and adding a further equimolar quantity of diazotised 1,4-phenylenediamine from stage (1); and
(4) coupling the diazotised disazo dye formed in stage (3) with approximately 2 molar equivalents of 1,3-phenylenediamine to give the dye of Formula (3).
The dyes of Formulae (4) to (6) may be prepared using methods analogous to those used for the preparation of similar azo dyes. A suitable method comprises:
(1) diazotising 4,4′-diamino-stilbene-2,2′-disulphonic acid using, for example, sodium nitrite in a mineral acid at 0 to 5° C.; and
(2) coupling the diazonium salt from stage (1) with approximately 2 molar equivalents of a compound XH, preferably under mildly alkaline conditions. For the dye of Formula (4) the compound XH is 2-amino-8-naphthol-6-sulphonic acid. For the dye of Formula (5) the compound XH is 8-amino-1-naphthol-3,6-disulphonic acid. For the dye of Formula (6) the compound XH is an approximately equimolar mixture of 8-amino-1-naphthol-3,6-disulphonic acid and 2-amino-8-naphthol-6-sulphonic acid.
The dye of Formula (7) wherein R
1
is —SO
2
CH
2
CH
2
OSO
3
H, is commercially available as Colour Index Reactive Black 31. The dye of Formula (7) may be prepared using conventional methods for the preparation of azo dyes. For example a suitable method comprises:
(1) diazotising 2-amino-8-naphthol-6-sulphonic acid and coupling the resultant diazonium salt with the pyrazolone compound of the formula:
(2) diazotising the compound of the formula:
wherein R
1
is as hereinbefore defined;
(3) coupling the diazonium salt from stage (2) with the product of stage (1), preferably under alkaline conditions; and
(4) heating the azo dye formed in stage (3) in the presence of cuprammonium sulphate and a suitable alkanolamine, for example dihydroxyethylamine, to give the dye of Formula (7).
When R
1
is hydroxyethylsulphonyl, it is preferred that the dye is prepared by hydrolysing a dye of the Formula (7) wherein R
1
is —SO
2
CH
2
CH
2
OSO
3
H under mildly alkaline conditions.
We have found that the addition of a yellow dye to a composition according to the first aspect of the present invention results in further improvements in print quality when the composition is incorporated into an ink for use in an ink jet printer. Accordingly, a second aspect of the present invention provides a composition comprising:
(i) a composition according to the first aspect of the present invention; and
(ii) a water-soluble yellow dye.
Preferably the water-soluble yellow dye is a water-soluble yellow azo dye, which carries one or (more preferably) two
Lavery Aidan Joseph
Meyers John Parker
Avecia Limited
Klemanski Helene
Rothwell Figg Ernst & Manbeck
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