Patent GB-424588-A (GB)
Title: Vat and sulphur dyestuff preparations for textile printing
Filed: 1933-08-25
Abstract: Dye preparations; printing.--Vat or sulphur dyestuff preparations, suitable for addition to textile printing pastes, contain a di-(hydroxyalkyl) sulphoxide such as thionyldiglycol or thionyldiglycerol.  These compounds serve to increase the printing strength and the speed of fixation of the dyestuffs.  They may be added to pastes suitable for printing with previous reduction, e.g. one containing the dyestuff mixed with glycerol, water, caustic soda, sodium carbonate, British gum, starch and sodium benzylsulphanilate, and (added at 70 DEG  C.) sodium formaldehyde sulphoxylate and sodium hydrosulphite, or to pastes suitable for printing without previous reduction, e.g. one containing the dyestuff mixed with water, tragacanth, industrial gum, starch, British gum, glycerol, potassium carbonate and sodium formaldehyde sulphoxylate.  The addition may be made at any stage in the manufacture of the printing preparations, e.g. (a) an aqueous pressed cake containing 12--40 per cent of dyestuff may be stirred with an aqueous solution of the sulphoxide, if desired, in presence of glycerol or other water-soluble polyhydric alcohol, and the mixture be milled and sieved to obtain a uniform smooth paste which does not dry up, freeze or form encrustations or deposits even on prolonged storage prior to working up to form the printing paste; (b) the finely ground dyestuff may be intimately mixed with the finely ground sulphoxide, advantageously with addition of an emulsifying agent; (c) an aqueous pressed cake containing the dyestuff may be evaporated to dryness in presence of the sulphoxide and, if desired, in presence of dextrin or an emulsifying agent; (d) the dyestuff may be reduced, as by hydrosulphite, in presence of glycerol, thiodiglycol, thiodiglycerol or other water-soluble polyhydric alcohol with previous, simultaneous or subsequent addition of the sulphoxide; (e) the sulphoxide may be incorporated directly in the printing preparation, e.g. an aqueous thickening containing starch, British gum, industrial gum, tragacanth, potassium carbonate and sodium formaldehyde sulphoxylate may be stirred into a mixture of the aqueous dyestuff paste with glycerol and thionyldiglycol.  The printing preparations may contain other suitable additions, e.g. anthraquinone, hydroxyanthraquinones, aminoanthraquinones, anthraquinone sulphonic or carboxylic acids or salts thereof or the reduction products of anthraquinone derivatives still retaining oxygen in meso position (cf. Specifications 349,955 and 350,963). The printed material may be dried, subjected to the action of moist steam, developed in a solution containing potassium bichromate and acetic acid and soaped at the boil. Examples are given relating to the use in printing pastes obtained by the methods (a) to (e) above of the dyestuffs N-dihydro-1 : 2 : 1<1> : 2<1>-anthraquinoneazine and its 3 : 3<1>-dichloro derivative, the dyestuff from 6-methoxy - 3 - hydroxythionaphthene and 4-methyl - 6 - bromo - 2 : 3 - dihydro - 3 - ketothionaphthene - 2 - (p - dimethylamino)anil, 6 : 6<1> - diethoxy - 2 : 2<1> - bisthionaphtheneindigo, 6 : 6<1>-dichloro-4 : 4<1>-dimethyl-2 : 2<1>-bisthionaphthene-indigo, 2 : 7-dibromanthanthrone, dichloroisoviolanthrone and the carbazole of 4 : 5<1> - dibenzoylamino - a  : a -anthrimide.  Thionyldiglycerol is obtained by oxidation of thiodiglycerol, e.g. with hydrogen peroxide.