Aniline Leather

The dyes used for leather are mostly selected from ranges designed for textiles, paper, or foods, and pigments for printing, paints, plastics, and other applications. 

Besides shade, gloss is also an essential attribute, and special products like cationic fat liquors are used. Silicones give a very appropriate silky sheen often seen as a two-way (often called writing) effect on buffed leather. Most coat finishing processes also provide a glossy appearance. 

Alternative procedures are paddle dyeing for sensitive skins in an open vessel, and immersion dyeing, in which the leather passes through a dye solution and is subsequently squeezed by a roller. Spraying and roller machines have mostly replaced other techniques such as traditional brush dyeing, which colors the surface only. 

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Class Number Aniline leather Pigmented leather... 

In view of the above, aniline should be handled in areas with adequate ventilation and skin exposure should be avoided by wearing the proper safety equipment. Recommended personal protective equipment includes hard hat with brim, chemical safety goggles, hiU length face shield, mbber gaundet gloves, mbber apron, and mbber safety shoes or mbber boots worn over leather shoes. 

Polyamines as Coupling Components. Chrysoidines are obtained by coupling dia-zonium salts of aniline, toluidines, or mixtures thereof to polyamine coupling components such as 1,3-phenylenediamine, 2,4- or 2,6- toluylenediamine, or mixtures of these diamines. These dyes confer muted yellow to orange shades to paper, leather, and polyacrylonitrile fibers. When they are mixed with malachite green and fuchsin, medium-fast black shades are obtained on polyacrylonitriles. A mixture of chrysoidine with Crystal Violet or Victoria Pure Blue is used to adjust the color of nigrosine hectograph inks [1]. 

Basic azines are predominantly of historical interest. Yellow, red, brown, blue, and black shades can be obtained with these dyes. Today, Nigrosine Spirit Soluble is still used in shoe polish and creme. The sulfonated variety is applied as a leather dye. It is a polymeric dye containing phenazine ring systems, similar to Aniline Black. C.I. SolventBlack 5, 50415 [11099-03-9] (Nigrosine, spirit-soluble) C.I. Solvent Black 7, 50415 1 [8005-02-5] (4) is the free base. 

Uses Aniline is an oily liquid used in the manufacture of dyestuffs, intermediates for dyestuffs, and manufacture of rubber accelerators and antioxidant substances. Aniline has been extensively used as an intermediate in the manufacture of plastics, pharmaceuticals, pesticides, isocyanates, and hydroquinones. Occupational exposure to aniline is extensive and as diverse as its industrial uses. Workers associated with the manufacturing of acetanalide bromide, coal tar, colors and dyes, leather, disinfectants, nitraniline, perfumes, rubber, and photographic materials become victims of adverse effects from aniline. 

Uses Nitrobenzene is a colorless to pale yellow liquid. It has been used extensively in a variety of industries, (e.g., the manufacture of aniline dyes and soaps, as solvent for paints, for refining lubricating oils, as shoe polish, floor polish, dressings for leather products, the manufacture of explosives). 

Azo dyes 156 could be prepared by interaction of aniline 154 with secondary amine 155 followed by N-alkylation. Because of their good water solubility, salts 156 were used for dyeing or printing textiles, leather or synthetic materials (71DEP2020479, Scheme 52). 

Ex. 1. Windemuth teaches the practice of (a), a one part system. An isocyanate-terminated, viscous (in the melt), linear prepolymer is prepared from 2 moles of hexamethylene diisocyanate (II) and 1 mole of hydroxyl-terminated, linear polyester prepared from diethylene glycol and adipic acid. Two percent of hexa-hydrodimethyl aniline (a basic catalyst) is added to this prepolymer dissolved in dry benzene. The solution is applied to adherend members (e.g., the two ends of a leather drive belt) and dried. Subsequent brief exposure of the coated parts to moist air, followed by their contact under light pressure, results in a tough, flexible, rubbery bond in 2 to 3 hr. 

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