Patent GB-820626-A (GB)
Title: Water-insoluble chromiferous dyestuffs and process for their manufacture
IPC: C09B45/48
Filed: 1955-12-09
Abstract: The invention comprises water-insoluble dyestuffs which are isothiuronium salts of which the anion is that of a chromiferous monazo dyestuff.  They are made by reacting an acid chromiferous monoazo dyestuff, advantageously present as an alkali metal salt, with an isothiourea derivative, advantageously in an aqueous near neutral or weak acid medium at elevated or ambient temperatures. Indicated acid dyestuffs are those containing sulphone, sulphonamide, carboxylic acid and especially sulphonic acid groups.  Although 1,2-chromium complexes may be used preferred dyestuffs are 1,1-complexes containing sulphonic acid groups. Indicated isothiourea derivatives are isothiuronium bases and preferably isothiuronium salts of organic, e.g. acetic and sulphonic acids, and particularly inorganic acids, e.g. hydrochloric acid, and mixtures thereof. S-Aryl-isothiuronium halides are mentioned, preferred being salts which contain bound to the S atom of the ion an aliphatic, alicyclic or heterocyclic residue, e.g. S-alkyl- and cycloalkyl-isothiuronium chlorides, or a residue, advantageously aromatic, bound through an alkylene or alkylidene group.  Advantageously the S-substituent is free of groups imparting water-solubility.  Indicated as groups that may be present in the S-substituent are carbalkoxy, ether and keto groups.  Particularly preferred are S-alkyl- and aralkyl-isothiuronium salts which contain at least 4 C atoms in the cation.  Specified derivatives are S-methyl-, -ethyl-, -isopropyl-, tert.-butyl-, -tert.-amyl-, -cyclohexyl- and -dodecylisothiuronium chlorides and bromides, S-carbomethoxy- and -ethoxy-methyl-, -acetonyl- and especially -benzyl-isothiuronium chlorides.  The products colour lacquers, especially nitrocellulose, spinning masses such as those of acetylcellulose, and natural or synthetic waxes and resins such as P.V.C. cellulose esters and celluloid.  In examples illustrating the preparation of the dyestuffs and their use in colouring processes, brown, blue, orange and black pigments are obtained when 1,1-chromium complexes of dyestuffs derived from 4-chloro- and -nitro-6-sulpho-2-aminophenols and 1-amino-2-naphthol-4-sulphonic acid as diazo components and 1-naphthol-8-sulphonic acid and 1-(31-sulphophenyl)- and -phenyl-3-methyl-5-pyrazolones as coupling components and a 1,2-complex of the dyestuff 6-nitro-1-amino-2-naphthol-4-sulphonic acid \sY 2-naphthol are treated with certain of the above-specified isothiuronium salts, S-benzyl-thiuronium acetate also being used.ALSO:Water-insoluble dyestuffs which are isothiuronium salts of which the anion is that of a chromiferous monoazo dyestuff are used to colour spinning masses, especially those of acetyl-cellulose.  In Examples 2 and 3, cellulose acetate spinning masses are coloured respectively in black and orange shades by the salt formed from 5-amyl-isothiuronium chloride and the 1,2-chromium complex of the dyestuff 6 - nitro - 1 - amino - 2 - naphthol - 4 - sulphonic acid --> 2-naphthol and the salt from 5-dodecyl-isothiuronium chloride and the 1,1-chromium complex of the dyestuff 4-nitro-2-aminophenol -6-sulphonic acid --> 1-phenyl-3-methyl -5-pyrazolone.