Patent GB-319420-A (GB)
Title: Improvements in the treatment of materials made of or containing cellulose esters
IPC: D06P5/15
Filed: 1928-06-26
Abstract: 319,420. British Celanese, Ltd., and Ellis, G H. June 26, 1928. Yarns, treating with liquids.-Yarns made of or containing cellulose acetate or other organic esters of cellulose, for example cellulose formate, propionate or butyrate, or the products obtained by treating alkalized cellulose with esterifying agents, such as p-toluene sulphochloride, are subjected separately to partial or superficial hydrolysing and to weighting treatments. The treated materials acquire an increased resistance to hot treatments such as ironing, and possess affinity for a very wide range of colouring matters. They are also very suitable for the production of white or coloured discharge effects, both with reduction discharges, such as formaldehyde-sulphoxylate or formaldehyde-hydrosulphite discharges, and with oxidation discharges such as chlorate discharges, with or without cataylsts, such as salts of iron or vanadium. The weighting may be carried out by any suitable process, such as the processes described in Specifications 258,874, 259,899, 260,290, 277,602, 280,094, 281,084, 284,798, 285,941 and 309,876, and the hydrolysis, which may either precede or follow the weighting treatment, may be carried out by means of any suitable alkaline reagent, such as caustic soda or potash, sodium aluminate, or sodium silicate. Where the hydrolysis follows the weighting treatment, it may be combined with the process of fixing the weighting agent in the material. The material may, for example, be first treated with a solution of stannic chloride or chlorthiocyanate, and thereafter treated with a solution containing both a fixing agent, such as disodium hydrogen phosphate, and a hydrolytic agent, such as caustic soda.. The fixing or hydrolytic process may also be combined with a dyeing process. Reduction discharges may be applied for discharging direct cotton dyes or insoluble azo dyes which have been applied in dispersed form, or, with the addition of leucotropes they may be applied for discharging indigoid and anthraquinone vat colours and sulphur colours. The oxidation discharges, such as chlorates, may be applied for discharging di- and tri-arylmethane, thiazine, oxazine (including gallocyanines), azine, azo, xanthene and indigoid dyestuffs, as well as many of the insoluble dyes which are applied in dispersed form. The dyestuffs and discharges, (whether used before or after the dyestuffs) may be applied by any suitable dyeing, printing or stencilling method. The invention may be applied to mixed goods containing cellulose esters together with other fibres not deleteriously affected by the alkaline solutions employed in the hydrolytic treatment, such as cotton, or cellulose ether, viscose or cuprammonium artificial silks. Yarns or threads containing cellulose esters which have been treated according to the invention may also be twisted, woven or otherwise made up with other fibres, such as wool or natural silk. By conducting the weighting and hydrolytic treatments separately in accordance with the invention (compare Specifications 302,775 and 306,611) the degree of weighting and hydrolysis can be effectively controlled, so that for example the gain in weight due to the weighting-treating may be substantially equal to the loss in weight due to the hydrolysis. In examples, (1) woven piece goods of cellulose acetate yarns are treated first with a solution of stannic chloride and ammonium thiocyanate, and then with a solution of disodium hydrogen phosphate and caustic soda, they are then dyed with Chlorazol fast blue 2BN, Chlorazol fast red K, and Chlorazol fast yellow 5GK and printed with a discharge containing gum arabic, anthraquinone, zinc oxide and formosul, (2) cellulose acetate woven goods, weighted and saponified as in example 1, are dyed with indigo, and printed with a paste containing Leucotrope W, sodium formaldehyde sulphoxylate, anthraquinone, zinc oxide, and gum arabic, and (3) cellulose acetate woven piece goods are steeped in formic acid, immersed in stannic chloride solution, and then treated with disodium hydrogen phosphate; the goods are then simultaneously saponified and dyed in a bath containing Chlorazol fast red K and caustic soda.