Patent GB-500120-A (GB)
Title: Dry dyestuff preparations
IPC: C09B9/02
Filed: 1937-07-30
Abstract: 500,120. Dye preparations. FAIR. WEATHER, D. A. W., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. July 30, 1937, No. 21232. [Class 2 (iii)] Dry preparations of water-soluble salts of sulphuric esters of leuco anthraquinone vat dyestuffs are obtained by mixing an aqueous paste or solution containing such a watersoluble salt with a water-soluble organic liquid, boiling below 100‹ Q., which does not react with or appreciably dissolve the ester dyestuffs, a water-soluble dispersing agent or agglutinant and a small proportion of an alkali or strong organic base, removing the liquid from the mixture by filtering or centrifuging, washing, if necessary, with the organic liquid and subjecting to a mild drying treatment. Specified organic liquids are methyl and ethyl alcohols and specified dispersing agents or agglutinants are dextrin, glucose, sulphite cellulose liquor and formaldehyde-naphthalenesuphonic acid condensation products. The alkali may be, in part, that already present in the ester dyestuff paste. Additional substances, e.g. urea, may be incorporated to increase the solubility or as diluents. In examples : (1) dextrin, methyl or ethyl alcohol and potassium hydroxide powder are successively stirred into an aqueous paste of the sodium salt of the sulphuric ester of leuoodimethoxydibenzanthrone containing some sodium carbonate and the mixture is filtered, washed with methyl or ethyl alcohol containing potassium hydroxide, dried at 30-40‹ C. and powdered; (2) an aqueous paste of the potassium salt of the tetrasulphuric ester of 3 : 3<1> - dichlorodianthrahydroquinoneazine, containing some sodium carbonate, is mixed with an aqueous mucilage containing dextrin and potassium hydroxide, the mixture is stirred into ethyl alcohol containing potassium hydroxide and the granular precipitate is filtered off, washed with ethyl alcohol containing potassium hydroxide, dried at 40-45‹ C and powdered; (3) a similar aqueous paste is mixed successively with an aqueous solution of glucose and with ethyl alcohol containing potassium hydroxide and the product is further treated as in (2); (4) an aqueous paste of the potassium salt of the tetrasulphuric ester of 3 : 3<1>-dibromodianthrahydroquinoneazine, containing some sodium carbonate, is mixed with an aqueous mucilage containing dextrin and potassium hydroxide, the mixture is stirred into ethyl alcohol containing potassium hydroxide and the product is further treated as in (2); (5) dextrin and ethyl alcohol containing potassium hydroxide are successively mixed into an aqueous solution of the potassium salt of (2), containing some sodium carbonate, and the product is further treated as in (2); (6) dextrin and an aqueous paste of the potassium salt of (2), containing some sodium carbonate, are successively mixed into ethyl alcohol containing potassium hydroxide and the product is further treated as in (2) ; (7) dextrin and potassium hydroxide powder are successively stirred into an aqueous paste, containing some sodium carbonate, of the sodium salt of the leuco sulphuric ester obtainable by treating nitrodibenzanthrone with copper and pyridine-sulphur trioxide in pyridine and methyl alcohol is stirred into the mixture which is -then filtered, washed with methyl alcohol containing potassium hydroxide, dried at 27-30‹ C. and powdered ; (8) and (9) an aqueous paste of the sodium salt of the sulphuric ester of leuco - dichloroisodibenzanthrone or of leuco-dibromopyranthrone, containing some sodium carbonate, is mixed with a suspension of dextrin in methyl alcohol containing potassium hydroxide and the mixture is filtered and further treated as in (7) ; urea may be added ; (10) and (11) an aqueous paste of the sodium salt of the sulphuric ester of leuco-dibenzanthrone, containing some sodium carbonate, or of the disulphuric ester of leucoflavanthrone, containing some triethanolamine, is mixed with a suspension of dextrin in methyl alcohol containing sodium hydroxide and the mixture is filtered, washed with methyl alcohol containing sodium hydroxide, dried at 27-30‹ C. and powdered; urea may be added ; (12) an aqueous paste containing triethanolamine and the sodium salt of the sulphuric ester of leuco-pyranthrone (cf. Specification 247,787, [Class 2 (iii)]) is added with dextrin and more triethanolamine to methyl alcohol and the mixture is filtered, washed with methyl alcohol containing triethanolamine, mixed with some methyl alcohol and triethanolamine, dried at 27-30‹ C. and powdered. Specifications 288,358, 333,147, [both in Class 2 (iii)] 378,034, and 443,998 also are referred to.