A WATER SOLUBLE DIRECT BLACK POLYAZO DYESTUFFS MIXTURE

Abstract: A water soluble direct black polyazo dyestuffs mixture comprising trisazo dyestuffs, polyazo dyestuffs and disazo dyestuffs.

Description: This invention relates to a water soluble direct black polyazo dyestuffs mixture. The water soluble direct black benzidine dyestuff known as Direct Black 38 (C.I. No. 30235) imparts a jet black shade on cellulose materials such as cotton or jute fibres or paper, wool, silk, nylon or leather. [The abbreviation C.I. is a reference to the Colour Index published by Society of Dyers and Colourists, the United Kingdom and American Association of Textile Chemists and Colourists, the United States of America]. Benzidine is reported to be carcinogenic and has already been banned in some countries and is being banned in several other countries. Strenuous efforts are, therefore, in progress to find water soluble direct black dyestuffs which are not benzidine based and which are substitutes for benzidine based water soluble direct black dyestuffs. British Patent Specification No. 1467656 discloses a water soluble trisazo dyestuff of formula III It is mentioned in British Patent Specification No. 1467656 that this dyestuff imparts a violet black colour to natural or synthetic polyamide fibres such as wool or nylon but is not particularly suited to market requirements. British Patent Specification No. 1467656 also discloses a mixture of water soluble trisazo dyestuffs of formulae I, II and III or of salts thereof such as sodium salts: It is mentioned in British Patent Specification No. 1467656 that this dyestuffs mixture imparts a black shade with reddish or green tinges on natural and regenerated cellulose fibres, natural and synthetic polyamide fibres and leather. It is also mentioned in British Patent Specification No. 1467656 that this dyestuffs mixture, wherein the percentage of the dyestuffs of formulae I and II exceed 70 and 50 respectively, will not be suitable and commercially acceptable for want of acid and alkali sensitivity of its dyeings. Dyestuffs of formulae I and II have been disclosed in British Patent Specifications Nos. 1327915 and 1417428. As a result of extensive research and experiments we have been able to obtain a mixture of water soluble direct black polyazo dyestuffs, which is a selective admixture of polyazo dyestuffs and has been found to possess increased tinctorial value as compared to the trisazo dyestuffs mixture of the formulae I, II and III and imparts a jet black colour on cellulose materials such as cotton or jute fibres or paper, wool, silk, nylon or leather. According to the present invention there is thus provided a water soluble direct black polyazo dyestuffs mixture comprising: i. 20 to 30 parts by weight of a trisazo dyestuff of formula IV, wherein R is hydrogen, sodium or potassium; ii. 40 to 60 parts by weight of a trisazo dyestuff of formula V wherein R is as defined above; iii. 5 to 15 parts by weight of atrisazo dyestuff of formula VI, wherein R is as defined above; iv. 5 to 10 parts by weight of a mixture of polyazo dyestuffs of formulae IA, IIA and IIIA wherein R is as defined above and X is a lower alkyl group such as a methyl or ethyl group, a lower alkoxy group such as a methoxy or ethoxy group, a chloro or nitro group, a carboxy or sulfonic acid group or hydrogen at the 2, 3 or 4 position; and v. 2 to 5 parts by weight of a disazo dyestuff of formula VII, wherein R is as defined above. Preferably, the mixture of water soluble direct black polyazo dyestuffs in accordance with the present invention comprises ia. 22 to 27 parts by weight of the trisazo dyestuff of the formula IV, wherein R is as defined above; iia. 50 to 60 parts by weight of the trisazo dyestuff of formula V, wherein R is as defined above; iiia. 11 to 13 parts by weight of the trisazo dyestuff of formula VI, wherein R is as defined above; iva. 5 to 10 parts by weight of the mixture of polyazo dyestuffs of formulae IA, IIA and IIIA, wherein R and X are as defined above; and va. 2 to 5 parts by weight of the disazo dyestuff of formula VII, wherein R is as defined above. According to one embodiment of the present invention, the polyazo dyestuffs mixture of the present invention is formed by mechanically mixing the ingredients. According to another embodiment of the present invention, the polyazo dyestuffs mixture of the present invention is formed by first forming dyestuffs of formulae IV, V and VI in situ in known manner and thereafter mechanically mixing the mixture of dyestuffs of the formulae IV, V and VI with the remaining ingredients. The ingredients of the dyestuffs mixture of the present invention may be mixed in the dry state. Alternatively, the ingredient(s) of the dyestuffs mixture of the present invention may be mixed in the wet state and the dyestuffs mixture is then dried, preferably, at a temperature from 75 to 95°C. Dyestuffs of formulae IV and V have been disclosed in British Patent Specifications Nos. 1327915 and 1417428 and impart reddish black and greenish black shades respectively to cellulose materials such as cotton or jute fibres or paper, nylon, wool, silk or leather. A dyestuff of the formula VI has been disclosed in British Patent Specification No. 1467656 and imparts a violet black shade to cellulose materials such as cotton or jute fibres or paper, nylon, wool, silk or leather. A mixture of dyestuffs of the formulae IA, IIA and IIIA has been disclosed in our copending European Patent Application filed on even date herewith, and imparts a green colour to cellulosic materials such as cotton or jute fibres or paper. The dyestuff of the formula VII drawings is Direct Yellow 44 (Ref. C.I. No. 29000 in Colour Index) and imparts a yellow colour to cellulose materials such as cotton or jute fibres or paper, nylon, wool, silk or leather. The present invention will now be illustrated by the following Examples, in which all the parts are by weight: EXAMPLE 1 22.7 parts of 4,4′-Diaminobenzanilide was stirred with 98 parts of water and 58.7 parts of hydrochloric acid (30% w/v) for 30 minutes and cooled to 0°C with ice. The reaction mixture was tetra-azotised at 0-5°C with 13.8 parts of sodium nitrite in 22 parts of water and stirred for 1 hour and the excess nitrous acid was destroyed in sulphamic acid. 58.7 parts of sodium chloride was added to the reaction mixture followed by a solution of 30.33 parts of 1-amino-8-hydroxy-naphthalene-3,6-disulfonic acid in 155 parts of water and 15.65 parts of sodium hydroxide (25% w/v) over a period of 2 hours at 5-10°C. The reaction mixture was stirred for 1 hour and its pH was raised to 2.0 to 2.3 using 5 parts of sodium acetate. The reaction mixture was again stirred at 5-10°C for 6-8 hours followed by addition of 98 parts of sodium chloride and cooling to 0°C. To this was added aniline diazo prepared from 7.83 parts of aniline, 40 parts of ice, 29.33 parts of hydrochloric acid (30% w/v) and 5.83 parts of sodium nitrite at 0-2°C followed by a slurry of 58.7 parts of sodium carbonate in 120 parts of water to raise the pH to 9.0 to 9.2. The reaction mixture was stirred for 4 hours at 0.2°C and its temperature was raised to 15-20°C in 2 hours. Test for aniline diazo was negative. To this was added a solution of 2.74 parts of 1-amino-8-naphthol-4-sulfonic acid in 98 parts of water and 3.9 parts of soda ash and the mixture was stirred for 2 hours at 20°C. A solution made from 5.09 parts of m-aminophenol, 98 parts of water and 0.98 parts of sodium carbonate was then added to the reaction mixture and stirred for 2 hours at 20-25°C. The reaction mixture was neutralised to a pH from 6.8 to 7.2 using 17.26 parts of sulfuric acid as 20% w/v solution in water and was stirred for 1 hour at 20-25°C. 2.35 parts of m-Phenylenediamine (as 10% aqueous solution) was then added to the reaction mixture and stirred for 4 hours at 25-30°C. The mixture of dyestuffs of the formulae was salted out from the reaction mixture using 78 parts of common salt and filtered. The filter cake was mixed with the 10 parts of a mixture of dyestuffs of formulae and 5 parts of the dyestuff of the formula in a mixer. The resulting final mixture of water soluble direct black polyazo dyestuffs was dried in an electric oven at 90-95°C. The dyestuffs of the formulae 3A, 4A and 5A above have been disclosed in our copending European Patent Application [our ref: 58491], of even date herewith. EXAMPLE 2 23 parts of the triazo dyestuff of formula 1 of Example 1, 52 parts of the triazo dyestuff of formula 2 of Example 1, 12 parts of the triazo dyestuff of formula 3 of Example 1, 9 parts of the mixture of polyazo dyestuffs of formulae 3A, 4A and 5A of Example 1 and 4 parts of the disazo dyestuff of formula 6 of Example 1 were mixed in a mixer to obtain a water soluble direct black polyazo dyestuffs mixture. Using the dyestuffs mixtures of Examples 1 and 2, cotton fibres, jute fibres, paper, wool, silk, nylon and leather were dyed in known manner to obtain jet black colour on such materials. The tone and fastness properties of the above materials dyed with the dyestuffs mixtures of Examples 1 and 2 were found to be as good as those obtained with Direct Black 38 (C.I. No. 30235 in Colour Index) under identical dyeing conditions. The tone and fastness properties of the above materials dyed with the dyestuffs mixtures of Examples 1 and 2 were also found to be far superior to those obtained with the dyestuffs mixture of the formulae I, II and III of British Patent Specification No. 1467656 under identical dyeing conditions. It is, therefore, inferred that addition of the dyestuffs mixture of the formulae IA, IIA and IIIA and the dyestuff of the formula VII to the dyestuffs mixture of the formulae IV, V and VI and also selection of the various ingredients of the dyestuffs mixture of the present invention in the respective proportions set forth herein impart a synergistic effect to the dyestuffs mixture of the formula IV, V and VI thereby improving the dyeing properties of the dyestuffs mixture of the formulae IV, V and VI. The fact that the percentage of the dyestuff of the formula IV can be 20 to 30 parts by weight adds weight to this inference, so also the fact that the suitability and commercial acceptability of the dyestuffs mixture of the present invention will not be affected even if the percentage of the dyestuff of the formula V is above 50 and up to 60. The dyestuffs mixture of the present invention is thus an ideal substitute for Direct Black 38.

Claims: 1. A water soluble direct black polyazo dyestuffs mixture comprising i. 20 to 30 parts by weight of a trisazo dyestuff of formula IV, wherein R is hydrogen, sodium or potassium; ii. 40 to 60 parts by weight of a trisazo dyestuff of formula V wherein R is as defined above; iii. 5 to 15 parts by weight of a trisazo dyestuff of formula VI, wherein R is as defined above; iv. 5 to 10 parts by weight of a mixture of polyazo dyestuffs of formulae IA, IIA and IIIA wherein R is as defined above and X is a lower alkyl group such as a methyl or ethyl group, a lower alkoxy group such as a methoxy or ethoxy group, a chloro or nitro group, a carboxy or sulfonic acid group or hydrogen at the 2, 3 or 4 position; and v. 2 to 5 parts by weight of a disazo dyestuff of formula VII, wherein R is as defined above. 2. A dyestuffs mixture as claimed in Claim 1, which comprises: ia. 22 to 27 parts by weight of the trisazo dyestuff of formula IV; iia. 50 to 60 parts by weight of the trisazo dyestuff of formula V; iiia. 11 to 13 parts by weight of the trisazo dyestuff of formula VI; iva. 5 to 10 parts by weight of the mixture of polyazo dyestuffs of formulae IA, IIA and IIIA; and va. 2 to 5 parts by weight of the disazo dyestuff of formula VII. 3. A dyestuffs mixture as claimed in Claim 1 or 2, which is formed by mechanically mixing the ingredients. 4. A dyestuffs mixture as claimed in Claim 1 or 2, which is formed by first forming dyestuffs of formulae IV, V and VI insitu in known manner and thereafter mechanically mixing the mixture of dyestuffs of the formulae IV, V and VI with the remaining ingredients. 5. A dyestuffs mixture as claimed in Claim 3 or 4, wherein the ingredients are in the dry state. 6. A dyestuffs mixture as claimed in Claim 3 or 4, wherein the ingredient(s) is/are in the wet state and the dyestuffs mixture is dried at a temperature of from 75° to 95°C.

Inventors: BHATT, GIRISH ISHWARLAL, BHATT, MUKUNDBHAI RAVISHANKAR, KULKARNI, SUBRAO SHRINIVAS, UPASANI, CHANDRASHEKHAR BHANUPRASAD
Applicants: ATUL PRODUCTS LIMITED
Application year: 1986
Main classification: C09B67
IPC codes: C09B35, C09B67