This invention relates to mixtures of reactive dyes, their preparation and use.

Reactive dyes and their use for the coloration of substrates have been known for about forty years. More recently, liquid brands of reactive dyes have become popular, particularly for the printing of textiles. There is a need for a green reactive dye which has a high build-up, and good solubility in aqueous media.

According to the present invention there is provided a composition comprising a first, second, third and fourth dye, each of which is of formula (1) or a salt thereof:

wherein:

X is a labile atom or group;

A and B are each independently an optionally substituted phenylene group; one of R ¹ and R ² is H and the other is sulpho; one of R ³ and R ⁴ is H and the other is sulpho;

R ⁵ and R ⁶ are each independently Cι. ₄ -alkyl; and the first, second, third and fourth dye are different from each other.

X is preferably a quaternary ammonium group or halo, more preferably 3- or 4- carboxypyridinium, F or CI, especially Cl.

Preferably A and B are each independently sulphophenylene, more preferably sulpho-1 ,4-phenylene or sulpho-1 ,3-phenylene, especially sulpho-1 ,4-phenylene. The sulpho group is preferably ortho to the azo (-N=N-) group. Preferably A and B are identical to each other.

R ⁵ and R ⁶ are preferably methyl.

Preferably the first dye is of the formula (2):

(2) wherein:

R ¹ and R ³ are H and R ² and R ⁴ are sulpho. The second dye is preferably of formula (2) wherein R ¹ and R ³ are sulpho and R ² and R ⁴ are H. The third dye is preferably of formula (2) wherein R ¹ and R ⁴ are H and R ² and R ³ are sulpho. The fourth dye is preferably of formula (2) wherein R ¹ and R ⁴ are sulpho and R ² and R ³ are H.

Preferably the first, second, third and fourth dye each independently constitute 10 to 40 parts, more preferably 15 to 35 parts, especially 20 to 30 parts, more especially approximately 25 parts by weight in each 100 parts in total of the first, second, third and fourth dye.

Compositions according to the invention can be prepared by condensing a compound of formula (3) wherein A and B are as hereinbefore defined with a mixture of first and second compound of formula (4) wherein R ⁶ is as hereinbefore defined, and R ⁷ is H and R ⁸ is sulpho in the first compound and R ⁷ is sulpho and R ⁸ is H in the second compound. If desired, halo groups in the resultant composition can be replaced by quaternary ammonium groups by methods known in the art.

(3) (4)

The condensation is preferably performed at a pH in the range 4 to 8, more preferably 5 to 7. A temperature of 20 to 50°C is convenient. Normally the condensation is performed in water or an aqueous solvent.

Compounds of formula (3) can be prepared by diazotising nitroamines of formula H ₂ N-A-NO ₂ and H2N-B-NO2 (wherein A and B are as hereinbefore defined) and coupling the resultant diazonium salts onto 1-amino-8-hydroxynaphthalene-3,6-disulphonic acid and reducing the resulting dinitro compound to give a compound of Formula (3). Diazotisation is normally performed below 5°C using NaNO ₂ and dilute mineral acid. Compounds and mixtures of formula (4) may be prepared by condensing a cyanuric halide with appropriate aniline derivatives.

The dyes in the composition are preferably in the form of their sodium, potassium or lithium salt, or a mixed salt thereof.

As a result of their high water solubility, compositions according to the invention are useful for the preparation of high strength liquid dyes. Thus, a further feature of the invention provides a liquid dye comprising water and up to 30 parts, preferably 1 to 30 parts, more preferably 10 to 20 parts, of a composition according to the invention in each

100 parts of water, wherein all parts are by weight. The liquid dye may also contain solubility enhancing agents, e.g. urea, which assists strength and stability of the liquid dyes. The present invention also provides a process for colouring a substrate comprising applying thereto a composition according to the invention, preferably as a solution in water. The substrate is preferably a leather or a textile material having -OH or -NH- groups, for example wool, silk, polyamide and especially cellulosic materials e.g. cotton. The composition is preferably applied to cellulosic materials in conjunction with an acid binding agent, for example an alkali metal hydroxide, carbonate or bicarbonate.

Compositions of the invention colour textiles an attractive green shade and benefit from high solubility in aqueous media. This allows high strength solutions to be prepared and gives good storage stability to solutions of normal strength. Furthermore, the dyes have good dyeing properties, high substantivity high solubility and compatibility with other PROCION H-EXL dyes. This compatibility allows binary and tertiary mixtures to be made which give consistent dyeings over a variety of different dyeing conditions.

The invention is further illustrated by the following examples. Example 1

Staαe a.

A dyebase of the formula (5) was prepared by following the exemplified method of GB 1 ,387,925 (See page 2, lines 10 - 30).

(5)

Staαe b.

Cyanuric chloride (54.8 mmol) was dissolved in acetone and poured onto ice. 2-Methyl-4-sulphoaniline (24.9 mmol) and 2-methyl-5-sulphoaniline (24.9 mmol) were dissolved together in water at pH7 and added dropwise to the cyanuric chloride suspension at 0-5°C, pH 6. The mixture was stirred for 1hr, screened and then added to a screened solution of the product from stage a) (22.6 mmol) dissolved in water at pH 6. The mixture was stirred for 5 hours at 40°C, cooled to room temperature and salted to 15% w/v using NaCl. The resultant precipitate was filtered-off, dissolved in water and dialysed to remove unwanted salts. Removal of water by evaporation gave a composition containing four dyes of formula (2) (31.Og) in a weight ratio of roughly 1 :1 :1 :1 :

(2)

Wherein in the first dye R ¹ and R ³ are H and R ² and R ⁴ are sulpho; in the second dye R ¹ and R ⁴ are H and R ² and R ³ are sulpho; in the third dye R ² and R ⁴ are H and R ¹ and R ³ are sulpho; and in the fourth dye R ¹ and R ⁴ are sulpho and R ² and R ³ are H.

Stage c) Comparative Solubility Measurements

By way of comparison stages a) and b) were repeated except that in place of a mixture 2-methyl-4-sulphoaniline and 2-methyl-5-sulphonaniline there was used the individual anilines. The two resultant dyes had the structures shown below: Dve A

Dve B

The solubilities of Dyes A, B and the four-component composition from Stage b) in water at 20°C were as follows:-

Dye Solubility Mixture from Stage b) 14%

Dye A 8%

Dye B 2%

Example 2 The mixture from Example 1 , stage b) and Dyes A and B from Example 1 were applied to cotton at 1%,2%,4%,6% and 9% by exhaust dyeing. The build up was measured by assessing the strength of the dyeing on cotton by reflectance spectroscopy. The mixture was found to build up better than A and B alone at 1%, 2%, 4%, 6% and 9%.