Leather Condensation Dyes

The condensation on the fabric of 1-amino-3-iminoisoindo1enines or 2-amino-5-iminopyrro1enines with phloroglucinol, preferably in the presence of metal salts and solvents, yields fast dyeings in brown shades (158). Metallized azo dyes derived from phloroglucinol yield fast dyeings on leather (qv) or silk (qv) (159). 

The most widely reported developments have been in category 4, ie, 4,4 -dinitro-2,2 -stilbenedisulfonic acid (1) condensations with amino-containing azo components, some of which ate copper complexes, to give dyes having excellent properties on leather (19—31) (Table 2). 

Tannery B. This tannery, also located in New England, employs 80 workers who process about 700 hides per day producing fully tanned and colored leather which are shipped to a separate facility, Tannery E, for surface and mechanical finishes. During the site visit on October 12, 1978, 19 air samples and 4 bulk samples were collected. The air samples were collected at all stages of the tanning operation. The bulk samples consisted of two waste water specimens, one steam system condensate and one floor scraping from the dye room. 

For leather, the quinoline chromophore, prepared by condensation of quinoline derivatives with phthalic anhydride or similar substances, is of some interest. The mainly yellow or red compounds are sulfonate d and yield valuable dyes for leather, e.g., C.I. Acid Yellow2, 47010 (15). 

Initially, sulfur dyes were water-insoluble, macromolecular, colored compounds formed by treating aromatic amines and aminophenols with sulfur and/or sodium polysulfide. R. Vidal developed these dyes in 1893 but they only became attractive for leather with the introduction of water-solubilizing groups. Today, the sulfur dyes can be divided into three classes conventional water-insoluble, leuco, and solubilized sulfur dyes. Most sulfur dyes are synthesized by condensation of aromatic amines with sulfur or sodium polysulfide in the so-called bake process, or else in water or under pressure as a solvent-reflux reaction. 

Acid dyes Azoic colouring matters Basic dyes Developers Direct dyes Disperse dyes Fluorescent dyes Food dyes Ingrain dyes Leather dyes Mordant dyes Natural dyes Oxidation dyes Pigments Reactive dyes Reducing agents Solvent dyes Sulphur dyes Condense sulphur dyes Vat dyes... 

Coralon. [Hoechst AG] Aromatic condensate, neutral salt leveling agent for dyeing, chrome leather. 

Basic Violet 10 (Rhodamine B) is a dye for bast fibers, mordanted cotton, leather, and paper. Its salts with certain acids and acid dyes provide pigments (Pigment Violet 1, Pigment Red 173) and solvent dyes (Solvent Red 35, Solvent Red 109). Basic Violet 10 is prepared by condensing phthalic anhydride with m-diethylaminophenol and treating with hydrochloric acid. This is the general preparative route for rhodamines. 

---