DE595187C - Process for dyeing leather - Google Patents

Description

Process for dyeing leather It has been found that leather can be made real can dye if one uses copper compounds of azo dyes for dyeing, which are built up according to the scheme R1> R2 R3, where R1 is a lacquer-forming group. containing diazo compound, R2 a containing at least two hydroxyl groups, Benzene derivative capable of double coupling and R, a diazoazo compound, whose diazo group belongs to a monoaryl radical.

For the preparation of the azo dyes built up according to the above scheme, whose copper compounds are to be used in the present process diazo compounds (R1) containing lacquer-forming groups are the diazo compounds the benzene and naphthalene series, which in o-position to the diazo group is a hydroxyl, Contain carboxyl, alkoxy or the salicylic acid group, into consideration. Such diazo compounds are, for example, the diazo compounds of the o-aminophenols, o-aminonaphthols, o-aminoalkoxybenzenes, o-aminoalkoxynaphthalenes, anthranilic acids, o-aminonaphthalene carbonic acids, aminosalicylic acids and sulfonic acids, nitro, Alkyl and halogen substitution products of these bodies. As at least two hydroxyl groups Benzene derivatives (R2) containing and capable of double coupling come, for example z, 3-Dioxybenzene, r, 3-Dioxybenzene- ¢ -carb, onic acid, r, 3-Dioxybenzene-5-carboxylic acid, r, z, 3-trioxybenzene-5-carboxylic acid and their sulfonic acids, nitro, alkyl and Halogen substitution products, insofar as they are capable of double coupling, into consideration. Finally you can use the above scheme to prepare the azo dyes as diazoazo compounds whose diazo group belongs to a monoaryl radical (R3), for example q. - Diazoazobenzene-r-4'-sulfonic acid, 3, 2'-dimethyl-4.-diazoazobenzene-4'-sulfonic acid and q .'-Oxy-4.-diazoazobenzene-3'-carboxylic acid can be used.

The preparation of the azo dyes according to the above scheme by action the diazo compounds on the coupling component can be in different order be carried out and depending on the sequence chosen and the nature of the diazo compounds in a neutral, acidic or alkaline medium such as soda, bicarbonate, Alkaline earth, caustic alkali, ammonia, pyridine, acetic acid or hydrochloric acid containing: Medium. Likewise, the Copper compounds of the thus obtained Dyes by treating the dyes with a wide variety of copper-releasing substances Means manufactured "earth. Such copper compounds are, for example, copper sulfate, Copper chloride, tetramine cupric sulfate, copper acetate, optionally in the presence of organic bases such as pyridine. The copper donor can either on the monoazo dye containing lacquer-forming groups or on the fully formed Polyazo dye are brought into action. Furthermore, the treatment of the Dyes with the copper-releasing agents in the dyebath or at the same time as the Preparation of the dyes are carried out.

The copper-containing to be used according to the present process Azo dyes color tanned leather in any manner in an even brown to brown-violet to black-brown shades. These colorations are very acidic as well as alkali-fast and extremely lightfast.

Example i Neutralized chrome leather (box calf, cattle box, Chevreau, Chevrettes) in the barrel in 3 to 4 times the amount of water at 60 ° C. -During the rotation, a solution of the copper-containing dye is created through the hollow shaft from the azo dye 2-diazo-i-oxybenzene-4-sulfonic acid r i, 3-Dioxybenzol-3, 2'-Diinethvl-4-diazoazobeii7, ol-4'-sulfonic acid admitted. After about 40 minutes the dye has been absorbed by the leather, whereupon is greased as usual.

The leather dyed in this way shows a very full, rich brown hue, which is very real.

Examples Well-rolled, vegetable-tanned sheep or goat leather is, as indicated in example i, - colored neutrally. At the beginning of the dyeing process half the weight of the applied dye amount of formic acid is added, whereupon dyeing is continued for io to i_5 minutes. Afterwards it is rinsed.

leas leather dyed in this way has the same pale hue as the after Example i dyed leather.

In addition, the brush can also be used for neutral dyeing with cold liquor will.

The following table contains some of the dyes used as starting materials for the production of the copper compounds in the present process, specifying the color shades achieved with the copper compounds: i. Diazo component Coupling:, Diazo component Achieved color component clay with the Cu f R, 1 (R.,) 1R3 compound z. 2-Amino-i-oxybenzene-4-sul-, 3-dioxybenzene q. - Aminoazobenzene - ¢ '- sulfone- reddish fonsäure acid brown 2.2-Aniino-x-oxybenzene-4-sul- desgl. Dehydrothiotoluidinsulfonsäure- reddish fonsäure azo-i-amino-8-oxynaphtha- brown lin-3,6-disulfonic acid 3.2-Amino-i-oxybenzene-4-sul- desgl. 4-Nitro-i-aminobenzolazo-i-ami reddish fonsäure no-8-oxynaphthalene-3, 6-di-brown sulfonic acid 4.2-Amino-i-oxybenzene-4-sul- desgl. 4-Amino-q .'-oxyazobenzene-3'-car- reddish fonsäure Bonsäure Braun 5. 2-Amino-4, 6-dinitro-i-oxy- like. 3, 2'-Dimethyl-4-aminoazoben- reddish-tinged Benzene z01-4'-sulfonic acid brown 6.2-Amino-i-oxybenzene-4-sul- desgl. [-Amino-3-methoxyazobenzene- reddish fonsäure 3'-sulfonic acid brown 7. 6-Amino-4-sulfo-i-oxyben- like 3, 2'-dimethyl-4-aminoazoben- reddish zol-2-carboxylic acid zol-4'-sulfonic acid brown B.2-Axnino-i-oxybenzene-4-sul- desgl. Aminobenzolazo-i-aminonaph- violet brown Phonic acid thalin-6- (7) -sulfonic acid g.2-Amino-i-oxybenzene-4-sul- desgl. 4-Nitro-i-aminobenzolazo-i-ami violet brown fonsäure nonaphthalene-6-sulfonic acid 1o. q., 6-Dinitro-2-amino-i-oxy-i, 3-Dioxybenzene 4-Aniino-4'-oxyazobenzene-3'-car-brown Benzene 4-carboxylic acid Bonic acid The use of a copper-containing dye of a similar composition for dyeing leather has become known through the French patent specification 48i igo (Example 22, in connection with page g, lines 48 to 56). This dye dyes chrome leather in uneven tones and shows very poor drawability when dyeing vegetable-tanned leather. In contrast, the dyes used in the present process for any tanned leather have good drawability and dye in uniform tones. .

Claims (1)

PATENT CLAIM: Process for dyeing leather, characterized by the use of copper compounds of azo dyes, which according to the scheme Rl _r R2 R3 are built up, where R1 is a diazo compound containing lacquer-forming groups, R, a containing at least two hydroxyl groups, capable of two-fold coupling Bünzolderivat and R3 is a di, azoazo compound, the diazo group of which is a monoaryl radical belongs to represents.