Leather buffer

Leather buffers Pressure and friction Callosities on thumb... 

As far as clinical findings are concerned, there is no characteristic aspect, localization or clinical course of occupational contact dermatitis in tanners (Foussereau et al. 1982). Adams (1990) mentioned callosities as occupational marks caused by mechanical trauma on the thumbs of leather buffers, on the right index fingers of cutters and on the knuckles of glazers. 

The differences in the amino acid chemistry of the hide coUagen and the hair keratin are the basis of the lime-sulfide unhairing system. Hair contains the amino acid cystine. This sulfur-containing amino acid cross-links the polypeptide chains of mature hair proteins. In modem production of bovine leathers the quantity of sulfide, as Na2S or NaSH, is normally 2—4% based on the weight of the hides. The lime is essentially an unhmited supply of alkah buffered to pH 12—12.5. The sulfide breaks the polypeptide S—S cross-links by reduction. Unhairing without sulfide may take several days or weeks. The keratin can be easily hydrolyzed once there is a breakdown in the hair fiber stmcture and the hair can be removed mechanically. The coUagen hydrolysis is not affected by the presence of the sulfides (1—4,7). 

Miscellaneous. In ore flotation, sodium sulfite functions as a selective depressant. In textile processing, sodium sulfite is used as a bleach for wood (qv) and polyamide fibers and as an antichlor after the use of chlorine bleach. Synthetic appHcations of sodium sulfite include production of sodium thiosulfite by addition of sulfur and the introduction of sulfonate groups into dyestuffs and other organic products. Sodium sulfite is useful as a scavenger for formaldehyde in aminoplast—wood compositions, and as a buffer in chrome tanning of leather. 

Separation of amines was realized in an ODS column (250 x 3 mm i.d. particle size 5 /tm) at 30°C. The flow rate was 0.3 ml/min and amines were detected at 280 nm. Solvents A and B for gradient elution were ACN and 3 mM phosphate buffer (pH = 7). The gradient started with 15 per cent A for 2 min then to 60 per cent A in 50 min. Chromatograms illustrating the separation of amines are shown in Fig. 3.72. It was established that the recoveries of both SFE and MAE were higher than those of traditional solvent extraction, therefore, their application for the analysis of carcinogenic aromatic amines in leather is highly advocated [140],... 

Buffer action is especially important in biochemistry and analytical chemistry, as well as in many large-scale processes of applied chemistry. Examples of the latter inclade the manufacture of photographic materials, electroplating, sewage disposal, agricultural chemicals, and leather products. 

Aside from softening, a smaller amount of oils and fats as detergents are also used in preliminary cleaning of the raw skins and hides to suspend lime particles, buffer the alkaline solution that removes the epidermis and hair, and suspend these materials when they come off to remove grease to tan certain types of leather and to control the penetration of dyes. 

A number of techniques using similar concepts were developed over the years to treat leathers that had already deteriorated. Aqueous solutions of potassium lactate were routinely applied to the surface of bookbindings and other leather objects. Unfortunately, in many cases, the deleterious effects of the liquid water solvent on acidic leathers took place before the buffer salt neutralised the acid, resulting in dark, seriously embrittled leather. In order to avoid the effects of aqueous solutions, methods were tried employing ammonia vapour. The object was placed in an enclosed chamber over an open dish of ammonium hydroxide solution. However, ammonia vapour is a strong alkali and there is a danger that even with the use of dilute solutions, leathers that were too acidic would be transformed into ones which were too alkaline. Another alternative was to use an organic base such as imidazole in a non-aqueous solvent. However, this was also liable to result in leathers that were too alkaline. 

Leather, P. et al. (1998). Exposure to occupational violence and the buffering effects of intra-organizational support. Work and Stress 12 161-78. 

An arbitrator, or a buffer Ralph mused. He sat in the remaining leather chair, mildly relieved that he wasn t having to look up at the two men anymore. Both of them were half a head taller than he (another Saldana trait). "I understand. Your Majesty."... 

NFPA Health 2, Flammability 2, Reactivity 0 Uses Emulsifier for oils, fats, and waxes, cosmetics, polishes, cleaners, soluble oils coupling solvent for sol. oils, wax emulsions, creams absorbent for acidic gases, organic synthesis textile/leather processing prod, of detergents/surfactants buffer in cosmetics corrosion inhibitor acid-salt catalyst pH buffer pharmaceutical intermediate, emulsifier... 

Uses Buffer mfg. of lithium stearate and other lithium soaps lubricating greases carbon dioxide absorbent (for submarines and space vehicles) esterification catalyst photographic developer stabilizer source of Li-6 isotope (used in prod, of tritium) in alkaline batteries (electrolyte additive) corrosion inhibitor in steam boilers dispersant in water-based alkyd paints leather ceramics buffer in cosmetics hair waving or straightening... 

Uses Emulsifier for creams/lotions, oils, fats, waxes, cosmetics, min. oil and paraffin wax emulsions, leather dressings, textile specialties, polishes, cleaners absorbent for acidic gases medicine buffer in cosmetics solubilizer, stabilizer, buffer in pharmaceuticals formaldehyde scavenger in curing U-F resins, phenolics amine soaps (metalworking fluids) synthesis of surfactants, vulcanization accelerators, pharmaceuticals chemical intermediate for paints, etc. 

Uses Solubilizer solvent for many org. and inorg. compds., plastic films dye solvent, dye assistant for textiles mfg. of methylamine denaturing alcohol In organic synthesis drug intermediate in mfg. of ampicillin, cephaclor, etc. solder flux ingred. plasticizer in leather, cloth films, coatings stabilizer humectant in paper accelerator buffer in lacquers, explosives, cosmetics prep, of hypnotics photochemicals biocides cryoscopy vehicle in pharmaceuticals antidote... 

Uses Buffer mfg. of lithium stearate and other lithium soaps lubricating greases carbon dioxide absorbent (for submarines and space vehicles) esterification catalyst photographic developer stabilizer source of Li-6 isotope (used in prod, of tritium) in alkaline batteries (electrolyse additive) corrosion inhibitor in steam boilers dispersant in water-based alkyd paints leather ceramics buffer in cosmetics hair waving or straightening Manuf./Distrib. AMC Chems. Alfa Aesar http //www.aifa.com] Am. Int l. http //www.aicma.com] BassTech Int l. Chemetall Foote Dastech Int l. FMC/Lithium http //www.fmciithium.com] Integra http //www.integrachem.com] J.T. Baker http //www.jtbaker.com] Pacific West Spectrum Quality Prods. http //www.spectrumchemicai.com] VWR Int l. http //www.vwrsp.com] Varsal Instruments http //www.varsai.com] Vopak USA http //WWW. vopakusa. com... 

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