Disperse dye mixture

Details Disperse dye mixture Disperse dye mixture

2000-11-01

2003-05-13

Einsmann, Margaret (Department: 1751)

Bleaching and dyeing; fluid treatment and chemical modification

Multiple chemically diverse fibers or fibers with different...

Polyester fiber and cellulose fiber

C008S533000, C008S638000, C008S639000, C008S922000

Reexamination Certificate

active

06562082

ABSTRACT:

This invention relates to mixtures of disperse dyes, compositions comprising a dispersion of such a mixture and processes for the colouration of synthetic materials with such mixtures. More particularly, the invention relates to a mixture comprising at least two monoazo dyes. The two monoazo dyes each have respective aromatic nuclei linked by an azo group, one of the aromatic nuclei in each dye having a dialkyl- or dialkenyl- group para to the azo group. In a first such dye of the mixture, the other aromatic nucleus is a benzene ring substituted by a nitro group (some of which dyes tend to be reddish blue in colour), while in a second such dye, the other aromatic nucleus is a thiophene nucleus substituted by a nitro group (some of which dyes tend to be green in colour).
EP-A-0300626 discloses mixtures of dyes containing only dyes of the abovementioned first type having a nitrobenzene group; while each of EP-A-0347685 and WO-A-97/04030 discloses mixtures of dyes of the first and second types containing nitrobenzene and nitrothiophene groups respectively.
However, it is found that certain mixtures, although giving bright reddish blue shades on polyester when viewed in normal daylight, tend to exhibit a “red” flare in tungsten light which is a serious commercial disadvantage.
Although the problem of “flare” is solved by at least one mixture disclosed in EP-A-0300626, this is achieved at the cost of brightness; such a mixture gives a relatively dull shade. Similarly, this problem of “flare” may be solved by at least one of the mixtures disclosed in EP-A-0347685, but such a mixture is especially sensitive to reduction and has relatively low heat fastness. Likewise flare can be avoided by using a dye mixture in which the nitrothiophene carries an acetyl group. However, such dyes tend to be expensive.
We have found surprisingly that a mixture of dyes, as defined below, surprisingly not only allows reduction or even elimination of the “red” flare, but provide a brighter shade, are less sensitive to reduction and have a higher heat fastness than other known mixtures and at less expense.
Thus, the invention provides a mixture of dyestuffs containing at least
(A) at least one dye of the formula
 wherein
X is Cl, Br or I;
Q is C
1-4
alkyl; and
each of R
1
and R
2
, independently, is C
1-4
alkyl or C
1-4
alkenyl; and
(B) at least one dye of the formula (II)
 wherein
Q
1
is C
1-4
alkyl; and
each of R
3
and R
4
, independently, is C
1-4
alkyl or C
2-4
alkenyl.
An especially preferred value of X is Br, especially preferred values of Q and Q
1
are a methyl and ethyl and especially preferred values R
1
, R
2
, R
3
and R
4
are methyl, ethyl and allyl.
Especially preferred mixtures contain respectively,
(a) a dye of the formula (I), wherein X is Br, Q is methyl and each of R
1
and R
2
is ethyl [dye (1)] and a dye of the formula (II), wherein Q
1
is methyl and each of R
3
and R
4
is ethyl [dye (2)] (which dye is known as CI Disperse Green 9), more preferably such a mixture in which the ratio of dye (I):dye (II) is 91.5:8.5,
(b) a dye of the formula (I), wherein X is Br, Q is ethyl and each of R
1
and R
2
is ethyl [dye (3)] (which dye is known as CI Disperse Blue 183) and a dye of the formula (II) which is the abovementioned dye (2) (CI Disperse Green 9) and (c) a dye of the formula (I), wherein X is Br, Q is methyl and each of R
1
and R
2
is ethyl (dye (1) of mixture (a) above) and a dye of the formula (II), wherein X is Br, Q
1
is methyl and each of R
3
and R
4
is allyl [dye (4)].
A preferred ratio of dye (I):dye (II), by weight, is 98:2 to 50:50, more preferably 95:5 to 70:30, especially 93:7 to 85:15.
The individual dyes may be prepared in a conventional manner by diazotisation and coupling.
More particularly, (I), an amine of formula (III)
wherein X is Cl, Br or I, is diazotised and coupled with a coupling component of the formula (V)
wherein Q, R
1
and R
2
are as defined above.
For dye (II), an amine of the formula (IV)
is diazotised and coupled with a coupling component of the formula (VI)
wherein Q
1
, R
3
and R
4
are as defined above.
In the above diazotisation and coupling reactions, the diazotization is carried out using a diazotising agent, which is preferably nitrosyl sulphuric acid, optionally diluted with glacial acetic acid or a phosphoric/acetic acid mixture and preferably at a temperature of 0-10° C., more preferably 0-5° C. The coupling reaction is preferably carried out at a is temperature of 0-10° C., more preferably 0-5° C. and preferably at a pH<1 (say 0.5 ) up to 7, more preferably 0.5-1, followed by a subsequent increase in pH to 3-4 to isolate the dye.
The mixture of at least one dye of formula (I) and at least one dye of the formula (II) may additionally comprise at least one other dye, especially a yellow, orange, red or brown dye capable of producing a navy or black shade.
Mixtures embodying the invention can be prepared by a number of methods including
(1) Co-crystallisation
Typically, the dyes are dissolved in a hot solvent, for example, by placing the dyes in a suitable solvent and heating up to the reflux temperature of the solvent until the dyes are dissolved, thereafter filtering to provide a solution, and then allowing the solution to cool and crystals to form. The resultant mixture may then undergo further processing, such as milling and spray drying. Example of suitable solvents for this process are organic solvents such as aromatic hydrocarbons, chlorinated hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, alcohols, amides, sulphoxides, esters, ketones and ethers. Specific examples of organic solvents are toluene, ethyl cellosolve, acetone, chlorobenzene, pyridine, dimethyl formamide, diemthylsulphoxide, ethyl acetate, benzene, tetrahydrofuran and cyclohexane.
(2) Co-milling
(a) The dyes are mixed and then milled together to give an intimate blend which is then spray dried to give a solid mixture; or
(b) each dye is milled separately and then mixed in the required ratio before spray drying.
(3) Dry Blending
Each dye is spray dried separately and then mixed in the required ratio by a dry blending process.
The mixtures give an especially bright shade without exhibiting a red flare in tungsten light.
Mixtures embodying the invention provide especially useful disperse dyes valuable for colouring synthetic textile materials and fibre blends thereof, and may be formed into a dispersion for this purpose.
According to other aspects, the invention provides a composition comprising at least the dye mixture and a dispersing agent, surfactant or wetting agent, suitable for providing such a dispersion and also a process for colouring a synthetic textile material or fibre blend thereof which comprises applying to the synthetic textile material or fibre blend a mixture comprising at least one dye of the formula (I) and at least one dye of the formula (II).
The synthetic textile material may be selected from aromatic polyester, especially polyethylene terephthalate, polyamide, especially polyhexamethylene adipamide, secondary cellulose acetate, cellulose triacetate, and natural textile materials, especially cellulosic materials and wool. An especially preferred textile material is an aromatic polyester or fibre blend thereof with fibres of any of the above mentioned textile materials. Especially preferred fibre blends include those of polyester-cellulose, such as polyester-cotton, and polyester-wool. The textile materials or blends thereof may be in the form of filaments, loose fibres, yarn or woven or knitted fabrics.
The mixtures of dyes of formulae [I] and [II] optionally in conjunction with other disperse dyes may be applied to the synthetic textile materials or fibre blends by processes which are conventionally employed in applying disperse dyes to such materials and fibre blends.
Suitable process conditions may be selected from the following
(I) exhaust dyeing at a pH of from 4 to 6.5, at a temperature of from 125° C. to 140° C. for from 10 to 120 minutes an

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