Patent GB-438047-A (GB)
Title: Process for the manufacture of dyestuffs on cellulosic fibres
IPC: D06P1/32
Filed: 1934-05-10
Abstract: Dyes, forming on the material; printing; regenerated celluloses, dyeing; dye preparations.--Cellulosic materials are coloured by applying thereto by a printing or slop-padding process an a -hydroxynaphthalene compound, having a free vicinal b -position, an alkaline reacting agent and an oxidizing agent and developing the dyeing by oxidation.  The dyeings may be further treated with an oxidizing agent, preferably one, such as an alkali metal chromate, which forms a lake with the dyestuff.  Specified a -hydroxynaphthalene compounds are 1 : 4-, 1 : 5- and 1 : 7- dihydroxynaphthalenes, 1-methoxy - 4 - hydroxynaphthalene, 1 - amino-8-hydroxynaphthalene, 1 : 4 : 5 : 8-tetrahydroxynaphthalene, 1<1>-methyl - 5 - hydroxy - a  - naphthocarbazole, 2 - nitroso - 1 : 5 - dihydroxynaphthalene or the corresponding quinoneoxime and 5 : 8-dihydroxy-a -naphthoquinone.  These may be used as the free hydroxy compounds or the soluble salts, e.g. the sodium, potassium, ammonium or triethanolamine salts.  Specified alkaline reacting agents are sodium or potassium carbonate or hydroxide, ammonia and triethanolamine.  Specified oxidizing agents are alkali metal chromates, bichromates, chlorates or perborates, potassium ferricyanide, sodium m-nitrobenzenesulphonate, p-nitrosophenol, sodium nitroso - b  - naphtholate and p-nitrosodimethylaniline. Suitable catalysts, e.g. vanadates, may be used to promote the oxidation.  The printing preparations and slop-padding liquors may also contain anti-freezing agents, such as glycerol, ethylene glycol, diethylene glycol, thiodiglycol, thiodiglycerol or polyglycerol, and/or hydrotropic agents, such as sodium-m-nitrobenzenesulphonate or urea.  The following examples are specified: (1) Cotton is slop-padded three times at 35--50 DEG  C. with an aqueous solution containing 1 : 5-dihydroxynaphthalene, caustic soda and sodium m-nitrobenzenesulphonate and dried to obtain a brown dyeing fast to soaping; fastness may be improved by after-treatment with a solution of potassium bichromate and acetic acid or of salts of complex phosphotungstomolybdic acids; a deeper dyeing is obtainable when the slop-padded material is steamed for 5 minutes. (2) Viscose artificial silk is slop-padded three times at 35--40 DEG  C. with an aqueous solution containing 1 : 5-dihydroxynaphthalene and caustic soda, then, without drying, is slop-padded three times with an aqueous solution containing sodium m-nitrobenzenesulphonate, caustic soda and Glauber's salt and thereafter dried, steamed for 5 minutes, after-treated with a solution of potassium bichromate and acetic acid, soaped and dried to obtain a deep dark brown dyeing; if the sodium m-nitrobenzene-sulphonate is replaced by p-nitrosodimethylaniline, the dyeing is more reddish brown.  (3) Cotton or viscose artificial silk is printed with an aqueous paste containing 1 : 5-dihydroxynaphthalene, glycerol, potassium carbonate, nitroso b -naphthol and industrial gum, steamed for 3--5 minutes and after-treated with a solution of sodium bichromate and acetic acid to obtain a fast reddish brown print; if the nitroso-b -naphthol is replaced by p-nitrosodimethylaniline, the print is black.  (4) Cotton is slop-padded three times at 35--40 DEG  C. with an aqueous preparation containing 1 : 5-dihydroxynaphthalene, glycerol, p-nitrosodimethylaniline, sodium m-nitrobenzenesulphonate and caustic soda, dried, steamed for 5 minutes and treated for 5 minutes at 50--60 DEG  C. with a solution of potassium bichromate and acetic acid to obtain a black dyeing.  (5) Cotton is printed with an aqueous paste containing 1 : 4-dihydroxynaphthalene, glycerol, potassium carbonate, sodium m-nitrobenzenesulphonate and industrial gum and further treated as in (3) to obtain a brown print.  (6) By replacing the 1 : 4-dihydroxynaphthalene in (5) by the 1 : 8- and 1 : 7-dihydroxynaphthalenes, grey and powerful blackish grey prints respectively are obtained.  (7) 1 - amino - 8 - hydroxynaphthalene or its hydrochloride similarly gives a deep brownish black print.  (8) 1<1> - methyl - 5 - hydroxy-a -naphthocarbazole similarly gives a brown print fast to chlorine and to boiling.  (9) Cotton is printed with an aqueous paste containing 1 : 5-dihydroxynaphthalene, 5 : 8-dihydroxy - a  - naphthoquinone, sodium m-nitrobenzenesulphonate, dynamite glycerine, ammonia, potassium carbonate and industrial gum, Senegal gum, tragacanth, starch or British gum, dried, steamed and treated with a solution of sodium bichromate and/or copper sulphate and acetic acid to obtain a full black print fast to soaping, light and rubbing.  1<1> - Methyl - 5 - hydroxy - a  - naphthocarbazole is obtained by fusing with caustic alkali the corresponding 5-sulphonic acid obtainable by the Bucherer reaction from 1 : 5-naphthylaminesulphonic acid and o-tolylhydrazine.  The Specification as open to inspection under Sect. 91 comprises also the use as a -hydroxynaphthalene compounds of the reaction products of the known hydroxynaphthalenebisulphite addition compounds with amines or aminophenols.  This subject-matter does not appear in the Specification as accepted.