Patent GB-425433-A (GB)
Title: Process for dyeing leather
IPC: D06P3/32
Filed: 1934-04-20
Abstract: Azo dyes, soluble metal compounds of; mordant or acid wool dyes, dyeing with.--Fast dyeings on leather, other than alumina-chrome tanned leather, are obtained with the use of a water-soluble complex metal compound of a monoazo dye of the general formula <FORM:0425433/IV/1> wherein x is a lake-forming group in o-position to the azo group, R1 is an aryl residue containing no carboxy group in o-position to x and R2 is a residue of the benzene series. The use of the metal compounds described in Specification 401,544 (chromium, copper, iron, cobalt, nickel, manganese, vanadium and titanium compounds of azo dyes of the general formula <FORM:0425433/IV/2> wherein R is the residue of any coupling component carrying no --SO2.NH.Aryl group) is excluded.  Specified metals are aluminium, titanium, vanadium, chromium, copper, manganese, iron, cobalt, nickel and uranium.  The parent azo dyestuffs are those obtainable by coupling diazotized o-oxy-, o-alkoxy- or o-carboxysubstituted aminobenzenes or aminonaphthalenes further substituted, if desired, e.g. by chloro, bromo, nitro, sulpho, carboxy, methoxy or ethoxy groups, with a dioxybenzene, e.g. 1 : 3 - dioxybenzene, 1 : 3 - dioxybenzene - 4 or 5 - carboxylic acid, 1 : 2 : 3 - trioxybenzene - 5 - carboxylic acid or their sulpho, nitro, alkyl or halogen substitution products.  The following examples are specified.  (1) Neutralized chrome leather is dyed brown throughout by tumbling it for 40 minutes in a drum with water at 60 DEG  C. containing the nickel compound of the dyestuff, 4 - nitro - 2 - aminophenol - 6 - sulphonic acid --> 1 : 3 - dioxybenzene, and fatliquoring.  (2) Vegetable tanned sheep or goat leather is dyed a level full brown-olive very fast to light, by similarly tumbling it with a solution of the iron compound of the dyestuff, 4 - chloro - 2 - aminophenol --> 1 - 3 - dioxybenzene, adding formic acid and continuing the dyeing for 10--15 minutes; the dyeing may also be effected by brushing the leather with a neutral cold dyeing liquor. A table is also given showing the colours obtainable with the following dyestuffs, viz. the uranium, iron, manganese and cobalt compound of 4 - nitro - 2 - aminophenol - 6 - sulphonic acid --> 1 : 3 - dioxybenzene, the manganese, chromium (80 per cent) and nickel (20 per cent), chromium (50 per cent) and nickel (50 per cent), iron, cobalt and nickel compounds of 4 - nitro - 2 - aminophenol --> 1 - 3 - dioxybenzene, the nickel, cobalt and chromium compounds of 4-chloro - 2 - aminophenol --> 1 : 3 - dioxybenzene, the iron, cobalt, nickel, manganese and chromium compounds of 5-nitro-2-aminophenol --> 1 : 3 - dioxybenzene and 6 - nitro - 2 - aminophenol - 4 - sulphonic acid --> 1 : 3 - dioxybenzene, the cobalt, nickel, iron and manganese compounds of 4-chloro-2-aminophenol - 5 - sulphonic acid --> 1 : 3 - dioxy benzene, the iron, manganese, cobalt, nickel and chromium (67 per cent) and cobalt (33 per cent) compounds of 2 - aminophenol - 4 - sulphonic acid --> 1 : 3 - dioxybenzene, the cobalt, uranium, nickel, iron and manganese compounds of 4-methyl-2-aminophenol-6-sulphonic acid --> 1 : 3 - dioxybenzene and 4 - chloro 2-aminophenol - 6 - sulphonic acid --> 1 : 3 - dioxybenzene, the iron compound of 5 - chloro - 2 - aminophenol - 3 - sulphonic acid --> 1 : 3 - dioxybenzene, the copper compound of 6-nitro-2 - aminophenol - 4 - sulphonic acid --> 1 : 3 - dioxybenzene and the chromium (50 per cent) and copper (50 per cent) compound of 4-chloro-2 - aminophenol - 6 - sulphonic acid --> 1 : 3 - dioxybenzene.  Specification 305,949, [Class 15 (ii)], also is referred to.  The Specification as open to inspection under Sect. 91 comprises also the use of the metal compounds of the corresponding dyestuffs in which R2 is an aryl residue in general.  This subject-matter does not appear in the Specification as accepted.