Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2001-06-22
2003-04-22
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031520, C008S641000, C427S466000, C428S495000
Reexamination Certificate
active
06551390
ABSTRACT:
This invention relates to a composition comprising two or more yellow dyes, to liquid compositions and inks containing the dyes 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. The inks used in an ink jet printer are required to meet a number of criteria. For example they desirably provide sharp, non-feathered images which have good water-fastness, optical density and light-fastness. A high light-fastness is particularly important for photo-realistic prints prepared by means of an ink jet printer to minimise fading of the print over time.
Furthermore, the inks used in ink jet printers are required to dry quickly when applied to a substrate, however, they must not dry or crust over in the ink jet head as this can result in clogging of the ink jet nozzle. The inks are also required to be storage stable for long periods of time without deterioration in the properties of the ink. It has proved difficult to obtain an ink which is acceptable in all of the above properties, because optimisation of one ink property often has a detrimental effect on another.
EP 468 647 Al discloses yellow azo dyes which when incorporated into an ink provides prints which have an excellent water-fastness.
C.I. Direct Yellow 132 is known as a colorant for use in ink jet printing inks. U.S. Pat. No. 5,560,771 discloses a yellow ink containing C.I. Direct Yellow 86 and C.I. Direct Yellow 132 in a weight ratio of 1:3 to 3:1. The inks described in U.S. Pat. No. 5,560,771 are described as having a desirable shade and reduced nozzle clogging.
However, with the increasing popularity of using ink jet printers to produce photo-realistic prints there is a need for colorants having a high light-fastness. We have now found that mixtures of certain dyes are valuable as colorants for ink jet printing inks.
According to a first aspect of the present invention there is provided a composition comprising:
(a) a dye of the Formula (1) or a salt thereof; and
(b) a dye of the Formula (2) or a salt thereof:
wherein:
R
1
, R
2
, R
9
and R
10
each independently is H or C
1-4
-alkyl; and
R
3
, R
4
, R
5
and R
6
each independently is H, C
1-4
-alkyl, C
1-4
-hydroxyalkyl, C
1-4
-alkoxy halo;
R
7
and RB each independently is H, C
1-4
-alkyl, C
1-4
-hydroxyalkyl, or R
7
and R
8
together with the nitrogen to which they are attached form a 5- or 6-membered ring; and
a and b each independently is 1 or 2. R
1
, R
2
, R
5
, R
6
, R
9
and R
10
are preferably H.
Preferably R
3
and R
4
are each independently C
1-4
-alkoxy, more preferably methoxy.
Preferably R
7
and R
8
are each independently is C
1-4
-hydroxyalkyl, or R
7
and R
8
together with the nitrogen to which they are attached form a piperazine ring or, more preferably, a morpholine ring.
Preferably the sulpho groups in Formula (1) are attached meta to each azo group.
Preferably each of a and b has a value of 2. More preferably a and b are each 2 and the —COOH groups are attached meta to each azo group in Formula (2).
A preferred composition according to the present invention comprises a dye of the Formula (3), or a salt thereof, and a dye of the Formula (4), or a salt thereof:
Preferably the number of parts of component (a) is from 0.01 to 99.9, and the number of parts of component (b) is from 99.9 to 0.01; wherein the parts are by weight and the sum of the number of parts of component (a) and component (b)=100.
The compositions according to the first aspect of the invention exhibit a surprisingly high solubility in aqueous media compared to the individual dyes of the composition. Inks prepared using the compositions according to the present invention exhibit good operability when used in an ink jet printer. Furthermore, the inks provide prints with an attractive yellow shade, a high optical density and good water-fastness.
In a first preferred embodiment the composition comprises:
from 1 to 60, preferably 15 to 55, more preferably 35 to 45 parts of component (a); and
from 99 to 40, preferably 85 to 45, more preferably 65 to 55 parts of component (b);
wherein all parts are by weight and the sum of the number of parts of component (a) and component (b)=100.
We have found that when the compositions according to this first preferred embodiment are incorporated into inks for use in an ink jet printer they provide prints which exhibit a surprisingly high light-fastness compared prints obtained using inks containing the individual dyes of the composition alone.
According to a second aspect of the present invention there is provided a composition comprising a composition according to the first aspect of the present invention and C.I. Acid Yellow 23, or a salt thereof.
The C.I. Acid Yellow 23 further enhances the solubility of the composition in aqueous media and provides prints which exhibit a high chroma, whilst maintaining the high light-fastness and good optical density exhibited by the compositions according to the first aspect of the invention.
Preferred compositions according to the second aspect of the invention comprise:
(a) from 15 to 55, preferably 20 to 40 parts of a dye of the Formula (1) (more preferably of the Formula (3)), or a salt thereof;
(b) from 45 to 85, preferably 40 to 60 parts of a dye of the Formula (2) (more preferably of the Formula (4)), or a salt thereof; and
(c) from 5 to 40, preferably 10 to 20 parts of C.I. Acid Yellow 23, or a salt thereof;
wherein all parts are by weight and the total number of parts (a)+(b)+(c)=100; and
the dyes of the Formulae (1) to (4) are as hereinbefore defined.
The dyes present in the compositions according to the first and second aspects of the present invention may be in free acid form but are preferably in the form of salt. Preferred salts are alkali metal salts, especially lithium, sodium and potassium salts or ammonium and substituted ammonium salts. Especially preferred salts are those formed with sodium, lithium, ammonia, volatile amines and mixed salts therewith. Especially preferred mixed salts are mixed lithium and sodium salts because they exhibit a particularly high aqueous solubility and good light-fastness.
The dyes may be converted to the desired salt form using conventional techniques. For example, a dye may be precipitated in its free acid form by adding an appropriate acid to an aqueous solution of the dye. The acid form of the dye may then be treated with a suitable base such as to yield the desired salt. Alternatively, ion exchange techniques can be used to convert the dyes to the desired salt forms.
The dyes in the compositions according to the first and second aspects of the present invention may be, and preferably are, purified to remove undesirable impurities before they are incorporated into inks for ink jet printing. Conventional techniques may be employed for purifying the dyes, for example ultra-filtration, reverse osmosis and/or dialysis.
The dye of Formula (1) may be prepared using conventional methods for the preparation of azo compounds, for example a suitable method comprises: coupling a diazotized sulphoaniline with a compound of the Formula (5):
wherein R
1
, R
2
, R
3
and R
4
are as hereinbefore defined.
The dye of Formula (3) is commercially available from a number of suppliers as C.I. Direct Yellow 132.
The dyes of the Formula (2) may be prepared using conventional techniques for the preparation of azo compounds, for example the method described in Example 10 of EP 468 647.
C.I. Acid Yellow 23 is commercially available from a number of sources including Zeneca Limited and Aldrich.
According to a third aspect of the present invention there is provided a liquid composition comprising a composition according to the first or second aspect of the present invention and a liquid medium.
A preferred liquid composition comprises:
(i) 0.01 to 40 parts of a composition according to t
Lavery Aidan Joseph
Mahon Paul Francis
Watkinson Janette
Avecia Limited
Klemanski Helene
Pillsbury & Winthrop LLP
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