Patent GB-535668-A (GB)
Title: Improvements in printing fabrics of natural silk
IPC: D06P1/36
Filed: 1939-10-17
Abstract: 535,668. Dyeing textiles. DURAND & HUGUENIN AKT.-GES. Oct. 17, 1939, No. 28036. Convention date, Oct. 17, 1938. [Class 15 (ii)] Printing.-In printing fabrics of natural silk with a preparation, thickened with gum arabic or tragacanth, containing a chromium mordant dyestuff, a chromium salt of a fatty acid of low molecular weight which is substantially free from mineral acid constituents and, as described in Specification 511,424, another salt of a lower fatty acid, incapable of dissociating during steaming, or, as described in Specification 522,240, a salt of an isocyclic, heterocyclic or araliphatic carboxylic acid containing no sulphonic groups or group capable of forming with the chromium an internal metal complex salt, the process is modified, to obtain a more rapid fixation of the dyestuff and a softer feel in the printed areas, by a further addition to the preparation of an organic carboxylic acid capable of forming with the chromium an internal metal complex salt and by development by a steaming operation of a duration not exceeding two steaming periods of 8 minutes each. Alternatively the further addition may be of a salt of such a carboxylic acid. Specified carboxylic acids for this purpose are glycollic, aminoacetic, oxalic, lactic, tartaric, citric, salicylic, anthranilic, mandelic and phthalic acids. With sparingly soluble dyestuffs it is advantageous to add to the printing preparation urea with or without phenol and a liquid alcohol boiling above 100‹ C. In examples (1) to (5) an aqueous paste containing gum arabic, chromium acetate free from mineral acid salts, sodium formate and (1) lactic acid and the dyestuff. 4-nitroaniline-2-sulphonic acid # (acid) 1 : 8 : 3 : 6- aminonaphtholdisulphonic acid (alkaline) # 3-amino-4-sulphobenzene-azo-salicylic acid (cf. Specification 422,287), (2) oxalic acid and the dyestuff, 3-aminobenzene-azo-salicylic acid # N - acetyl - I : 8 : 4 : 6 - aminonaphtholdisulphonic acid cf. Specification 231,885, [Class 2 (iii)], (3) salicylic acid and the dyestuff obtainable by diazotizing and coupling with salicylic acid the product of reduction of the nitro group of 4-nitroaniline-2-sulphonic acid # salicylic acid cf. Specification 255,086, [Class 2 (iii)], (4) salicylic acid and the gallocyanine dyestuff obtainable by sulphonating the anilido product from nitroso-diethyl-m-toluidine and gallamide cf. Specification 301,329, [Class 2 (iii)], (5) salicylic acid and Chromocitronine R, is printed on a natural silk fabric, and the print is dried, steamed twice for 8 minutes and washed. In example (6), a natural silk fabric, dyed with p-amino-o-sulphosalicylic acid # (acid) 1 - amino - 2 - ethoxynaphthalene - 6 - sulphonic acid # (alkaline) the condensation product of 1:8:3: 6-aminonaphtholdisulphonic acid with salicylic acid sulphochloride cf. Specification 500,075, is printed with an aqueous paste containing gum arabic, chromium acetate free from mineral acid salts, sodium formate, sodium glycollate, zinc formaldehydesulphoxylate and Chromorhodine B, and the print is dried, steamed twice for 8 minutes, passed through a dilute solution of hydrogen peroxide and rinsed to obtain a red discharge of soft feel on a green ground. In example (7) the ground colour in (6) is replaced by 2-.aminophenol-6- carboxylic acid # (acid) 2 : 5 : 7-aminonaphtholsulphonic acid (alkaline) -6-nitro-2-aminophenol-4-sulphonic acid cf. Specification 490,965 and the discharge colour by Modern violet to obtain a violet discharge of soft feel on a grey ground. Specifications 435,701 and 453,834 also are referred to. The Specification as open to inspection under Sect. 91 comprises also the printing of animal fibres other than natural silk and includes an additional example in which a chlorinated woollen material is printed with an aqueous paste containing tragacanth, chromium acetate free from mineral acid salts, sodium formate, sodium oxalate the dyestuff of example (2) above and the print is steamed twice for 8 minutes and washed. This subject-matter does not appear in the Specification as accepted.