Patent GB-665587-A (GB)
Title: Azo printing and dyeing process
IPC: D06P1/12
Filed: 1949-12-05
Abstract: Cellulosic material is impregnated with an aqueous alkaline solution of a metalliferous dyestuff of the formula <FORM:0665587/IV (c)/1> where Me is a metal of atomic weight 58-64, Ar is an aryl radical, X is an o-hydroxy or carboxy residue, R is hydrogen or p  lower alkyl and Ar is free from further acid salt-forming substituents; the colour is then developed by applying a solution of a diazonium salt free from acid salt-forming substituents, and finally the material is treated with a mineral acid to neutralize the alkali metal bound by the dyestuff, and the acid is rinsed from the material.  The latter is then soaped, rinsed and dried or otherwise finished as usual.  Ar is preferably of the benzene or naphthalene series and may carry substituents such as chlorine, bromine, nitro, lower alkyl, sulphonamide or arylazo groups.  The diazo solution may be in the form of the chloride, bisulphate, aryl sulphonate or double salts of the chloride with zinc, cobalt or magnesium chloride or boron trifluoride.  For dyeing, the material is passed through the diazo solution, the latter having sufficient acidity to neutralize any free alkali from the impregnating bath.  For printing, the diazonium salt is made up into a thickened aqueous paste of sufficient acidity.  The mineral acid neutralizing bath has preferably a pH not above 2, and may be hydrochloric, sulphuric or phosphoric acid or sodium bisulphate.  Examples show dyeing and printing with the copper derivative of 2 - hydroxy - 5 - chlorobenzene - azo - resorcinol in the presence of alcohol and a sulphonated fatty acid derivative, developed with the zinc double chloride of diazotized 2-methoxy-5-chloroaniline.  Other suitable coupling components are 5-methyl- and 5-nitro-2-hydroxybenzene - azo - resorcinols, 5 - chloro - 2 - hydroxybenzene - azo - 21 - methyl - resorcinol, 3 : 31 - dimethoxy - diphenyl - 4 : 41 - bis - azo - resorcinol, 4 - (31 - sulphonamidobenzeneazo) - 5 - methyl - 2 - hydroxybenzene - azo - resorcinol, 2 - hydroxy - naphthalene - 1 - azo - resorcinol and 2 - carboxybenzene - azo - resorcinol. Suitable diazonium salts are those from o- and p-chloro- and nitro-anilines, 2 : 5-dichloraniline, 4 - nitro - o - toluidine, 2 - (41 - chlorphenoxy) - 5 - chloraniline, 4 - benzoylamino - 2 : 5 - diethoxyaniline, 4 - cyano - 2 : 5 - dimethoxyaniline, p : p1-diamino-diphenylamine, dianisidine and p-amino-o : o1-azotoluene.  The process is applicable to cotton and regenerated cellulose.  Specification 465,138 is referred to. Metallized arylazoresorcinols of the above formula are obtained by coupling the appropriate diazotized o-hydroxy, o-alkoxy or o-carboxy-amine with resorcinol or alkyl-resorcinol and heating the product with an aqueous solution or suspension of an oxide, hydroxide carbonate or other salt of the metal.  The production of the copper derivative of the dyestuff 2-amino-4-chlorphenol --> resorcinol is described.  The Specification as open to inspection under Sect. 91 is not limited to the use of mineral acid.  This subject-matter does not appear in the Specification as accepted.