Patent GB-420095-A (GB)
Title: The manufacture of vat and sulphur dyestuff preparations for textile printing
Filed: 1933-05-25
Abstract: Vat and sulphur dyestuff preparations, for use in printing textiles such as cotton, viscose, wool, cellulose acetate artificial silk or other animal or vegetable fibres, contain pyridine betaine or a salt thereof, e.g. the hydrochloride or hydrobromide, advantageously with the addition of glycerol or a similar polyhydric alcohol miscible with water, e.g. ethylene glycol, diethylene glycol, thiodiglycol or thiodiglycerol.  The addition of pyridine betaine or its salts may be made at any stage in the manufacture of the printing colour, e.g. by the following methods: (a) the dyestuff in the form of a pressed cake containing water is stirred with glycerol or similar alcohol and the assistant compound is added; (b) the dyestuff is finely ground and intimately mixed with the assistant, also finely ground; (c) the dyestuff in the form of a pressed cake containing water or of an aqueous paste is evaporated to dryness in the presence of the assistant, if desired in the presence of dextrine or an emulsifying agent; (d) the dyestuff is reduced in the presence of glycerine or similar alcohol with previous, simultaneous or subsequent addition of the assistant; (e) the assistant is added directly to the printing colour, e.g. together with glycerine to a printing colour comprising a dyestuff and a thickening containing wheat starch, British gum, industrial gum, tragacanth, potassium carbonate and sodium formaldehyde sulphoxylate.  The amount of assistant employed is preferably about 20--50 per cent of the weight of the dyestuff present.  If desired, there may be added compounds of hydrotropic character, also anthraquinone or derivatives thereof such as hydroxyanthraquinones, aminoanthraquinones, anthraquinone sulphonic or carboxylic acids or salts or such reduction products of these compounds as contain oxygen in the ms-position.  The development of the printings may be carried out by customary methods, e.g. by drying the printed material, treating it with moist steam, and developing the dyestuff by means of potassium chromate and acetic acid, followed by soaping at the boil.  In examples: (1) a printing colour is prepared by method (e) containing as dyestuff 6 : 6<1>-dichloro-4 : 4<1>-dimethylbisthionaphthene indigo or the sulphur dyestuff from carbazol indophenol and as assistant pyridine betaine hydrochloride; the same dyestuffs may be employed using methods (a) to (d); (2) a printing colour is prepared by method (e) using as dyestuff pyranthrone, one of the dyestuffs of German Specification 239,544, dibenzoylaminodianthraquinonyl - 1 : 1<1> - oxamide, Caledon Jade Green, the dianisidide of perylenetetracarboxylic acid (prepared by the process of British Specification 201,786, [Class 2 (iii)]), or isophthaloylaminoanthraquinone or other dyestuffs of the anthraquinonoid, indigoid or sulphur dyestuff series and as assistant pyridine betaine; (3) a printing paste which prints by the known method with sodium formaldehyde sulphoxylate and potassium carbonate without previous reduction comprises the dyestuff from mononitromethylbenzanthrone and sulphur (German Specification 242,621), dynamite glycerine, pyridine betaine hydrochloride and anthraflavic acid.  British Specifications 264,561, [Class 2 (iii)], 349,955 and 350,963 also are referred to.