Patent GB-447905-A (GB)
Title: Process for dyeing leather
IPC: D06P3/32
Filed: 1934-11-19
Abstract: Acid wool and mordant dyes, dyeing with; azo dyes.--Leather, especially chrome leather, is dyed, substantially throughout, with a monoazo dyestuff of the general formula <FORM:0447905/IV/1> wherein R represents the residue of p-aminobenzene either (a) N-substituted once or twice by methyl, ethyl or b -oxyethyl and, if desired, nuclearly substituted by halogen or a methyl, alkoxy or sulphonic acid group, or (b) N-substituted once by an acetyl group and also nuclearly substituted, X represents hydrogen or an amino or sulphonic acid group, and Y represents hydrogen, halogen or an amino, acidylamino, oxy, sulphonic acid, sulphonamide or sulphondialkylamide group, at least one of X and Y representing other than hydrogen.  The neutralized hides are dyed in the rotary cask with 150--200 per cent of water at 65 DEG  C., a solution of 1--2 per cent of the dyestuff being introduced through the hollow axle, the fat liquor being added after 45 minutes, and the cask being then kept in motion for a further 45 minutes, or longer in the case of heavy hides.  In examples, chrome leather is dyed with one of the following dyestuffs: (1) 2-amino-5-N-ethyl-b -oxyethylaminobenzenesulphonic acid --> 1-naphthol-3 : 6-disulphonic acid; (2) 2-amino-5-diethylaminobenzenesulphonic acid --> 8-chloro-1-naphthol-3 6-disulphonic acid; (3) 5-amino-2-ethylaminotoluene-4-sulphonic acid --> 1-naphthol-3-sulphonic acid-8-sulphonamide.  A table is also given showing the shades obtainable on the surface and in the interior of leather with various dyestuffs, additional diazo components being 4-ethylaminoaniline, 4 - diethylaminoaniline, 4 - ethyl - b  - oxyethylaminoaniline, 2- or 3-chloro-4-diethylaminoaniline, 2-chloro-4-dimethylaminoaniline, 4 - chloro - 5 - amino - 2-acetylaminoanisol, 3 - chloro - 2 - amino - 5-dimethylaminobenzenesulphonic acid, 2-amino-5 - diethylaminoanisol - 3 - sulphonic acid and 2 - amino - 5 - di - (b -oxyethyl)aminobenzenesulphonic acid and additional coupling components being 1-naphthol-3 : 8-disulphonic acid, 1 : 8-aminonaphthol - 3 : 6 - disulphonic acid, 1 : 8-aminonaphthol-6-sulphonic acid, 1-naphthol-3-sulphonic acid-8-sulphondimethylamide and 6-amino-1-naphthol-3-sulphonic acid. 3-Chloro-4-diethylaminoaniline is obtained by reduction of 3-chloro-4-diethylaminonitrobenzene which is obtainable by nitration of 2-chlorodiethylaniline, ethylation of 2 - chloro - 4 - nitraniline or interaction of 1 : 2-dichloro-4-nitrobenzene with diethylamine.  1 - Naphthol - 3 - sulphonic acid - 8 - sulphondimethylamide is obtained by introducing 1 : 8-naphthosultone-3-sulphonic acid into a concentrated aqueous solution of dimethylamine.  4-Ethyl-b -oxyethylaminoaniline is obtained by reducing with iron and hydrochloric acid nitroso-ethyl-b -oxyethylaniline obtainable by nitrosating ethyl-b -oxyethylaniline.  3 - Chloro - 2 - amino -5 - dimethylaminobenzenesulphonic acid, 2-amino-5-diethylaminoanisol-3-sulphonic acid and 2-amino-5-di-(b -oxyethyl)-aminobenzenesulphonic acid are obtained by causing the corresponding 2-nitroso compounds to react with a solution of a neutral alkali sulphite and heating the resulting solution with a mineral acid.  2-Nitroso-5-diethylaminoanisol is obtained by nitrosating 3-diethylaminoanisol.  The Specification as open to inspection under Sect. 91 comprises also the dyeing of leather with monoazo dyestuffs of the above general formula wherein R represents any benzene residue which, if it carries one or more nitro groups and/or halogen atoms, must also carry one or more amino, sulphonic acid or oxyalkylated hydroxyl groups, examples being given of the use of the dyestuffs, m-toluidine --> 6-amino-1-naphthol-3-sulphonic acid and 4-aminoanisol - 2 - sulphonic acid (obtained by sulphonation of p-anisidine) --> 1-naphthol-3 : 8-disulphonic acid, and a table specifying, as other suitable diazo components, aniline, 2-toluidine, p-xylidine, 2- or 4-amino-1-(b  : g -dioxy)propyloxybenzene, 3 - amino - 4 - (b  : g -dioxy)propyloxytoluene or its sulphuric acid ester, 4-chloro-2-amino-1-(b  : g -dioxy)propyloxybenzene, 3 - nitro - 1 : 4 - diaminobenzene, 4 - nitro - 2 - amino - 1 - oxyethoxybenzene, sulphanilic acid, 2-aminoanisol-4-sulphonic acid, 4-chloro-3-aminobenzenesulphonic acid, 4- or 5-nitro-2-aminobenzenesulphonic acid and 4-aminophenol-2-sulphonic acid and, as additional coupling components, 1-naphthol-3 : 6 : 8-trisulphonic acid, N-acetyl-1 : 8-aminonaphthol-3 : 6-disulphonic acid and 1 : 8 - dioxynaphthalene-3 : 6 - disulphonic acid.  This subject-matter does not appear in the Specification as accepted.