The Manufacture of Leather

Common salt (sodium chloride) has been used to preserve food since earliest times. It is, therefore, quite possible that naturally-occurring alum was first employed to treat skins when it was mistaken for common salt. The special properties of these particular crystals were noted and exploited for making 

It has been suggested that vegetable tanning developed from a desire to colour oil or alum-processed skins. Interestingly the earliest surviving recipes for the preparation of leather, dating from Babylonian times about 3000 years ago, show that a combination of these three processes were employed  

Certainly by the classical Greco-Roman period, vegetable tannage had developed into an important craft-based industry and little fundamental change appears to have occurred until the beginning of the nineteenth century. 

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The manufacture of leather foUows the same general steps for a great variety of leathers (Fig. 2). The largest category of hides taimed is catde hides. Of the cattle hides chrome tanning of unhaired hides is by far the dominant system used throughout the world. The tanning of other types of hides and skins requires variations in the systems used for cattle hides (3). 

Many enzymes have been the subject of protein engineering studies, including several that are important in medicine and industry, eg, lysozyme, trypsin, and cytochrome P450. SubtiHsin, a bacterial serine protease used in detergents, foods, and the manufacture of leather goods, has been particularly well studied (68). This emphasis is in part owing to the wealth of stmctural and mechanistic information that is available for this enzyme. 

Solvent-borne NR and quick-grab adhesives are commonly used in the manufacturing of leather footwear for temporary bonding and in rubber footwear... 

Shoe adhesives. CR adhesives are used for the permanent attachment of shoe soles. For difficult-to-bond sole materials (plasticized PVC, EVA foaming soles, thermoplastic rubber, SBR) graft polymer solutions of Neoprene AD-G combined with a polyisocyanate provide a good adhesion. Another major area for CR contact adhesives is the manufacture of leather goods, particularly leather shoe sole bonding and belt lamination. 

O.Rohm 1908 Trypsin, steapsin Preparation of hides for the manufacture of leather... 

The use of enzymes for the manufacture of leather played a major role for the industrial scale production of enzymes. For the preparation of hides and skins for tanning, the early tanners kept the dehaired skins in a warm suspension of the dungs of dogs of birds. Wood was the first in 1898 to show that the bating action of the unpleasant dungs was caused by the enzymes (pepsin, trypsin, lipase) which they contained. In the context... 

The following is a list of the materials which contain tannin in the largest quantities, and which may lie employed in the manufacture of leather. 

Leayes.—Of the foliage of trees containing tannin, very few, if any, are now employed in the manufacture of leather. The leaves of the heath were once extensively used in tins country but this material has long been abandoned, preference being given to oak barks and other substances of native and foreign growth,... 

OTHER COMMENTS utilized as a monomer, polymer, or eopolymer the monomer in the manufacture of leather finish resins, textile and paper eoatings, and plastic films primary use in production of acrylic and modacrylic fibers produces the hardest resin of the acrylate ester series. 

Rohm O (1908) Preparation of hides for the manufacture of leather. US Patent 886411 Ru MT, Wu KC, Lindsay JP et al. (2002) Towards more active biocatalysts in organic media increasing the activity of salt-activated enzymes. Biotechnol Bioeng 75(2) 187-196 Russell AJ, Beckman E J (1991) Enzyme activity in supercritical fluids. Appl Biochem Biotechnol 31(2) 197-202... 

Acetic acid is a colorless liquid with o pungent odor it is made synthetically from acetylene or by the oxidation of alcohol. It is soluble in water, alcohols, ethyl ether, and other organic solvents. It is used as a precipitant for albumen, casein, and rubber latex. It is also employed in the manufacture of leather, cordoge, linoleum, acetate solvents, acetyl derivatives, dyes, matches, printing inks, and polishes, and as an assistant in dyeing processes. 

In the manufacture of leather, ethanolamine-based chemicals are used for dressing, dyeing, and finishing. For paints and coatings, ethanolamines are employed both in production and in softeners and paint removers. 

Carboxylic acids are useful reagents and synthetic precursors. The two simplest ones are manufactured on a large scale industrially. Formic acid is employed in the tanning process in the manufacture of leather and in the preparation of latex rubber. It is synthesized efficiently by the reaction of powdered sodium hydroxide with carbon monoxide under pressure. This transformation proceeds by nucleophilic addition followed by protonation. 

Uses Fatting emulsifier In the manufacture of leather fatllquoring agents, textile auxiliaries, car shampoos, and alkaline and add Industrial detergents Properties Wh.-ylsh. Ilq. dens. = 1.02 cloud pt. = 10 C 60% act. 

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