皮革鞣制译文.doc

Abstract: This article clarifies both theory of hide preservation and the practical method. The author firstly indicates why the skin and hide need to be preserved and then discusses the factors, which influence the preservation of hide. Bacteria play a devil role and mostly cause the decay or other damages of the hide and skin. According to the characteristics of reacting to oxygen, bacteria can be classified as two types: anaerobic bacteria and aerobic bacteria. To limit bacterial growth or kill the bacteria, we can take the steps from four aspects: drying out the hide, using bactericide, pickle curing and lowering water activity. Combining these ideas into the practical commercial use of hide preservation, the salt curing is one of the most popular and effective means. The hides can be cured in an equipment of brine raceways and achieve the ultimate aim—preservation. They will be well ready for next tanning process. PRESERVATION OF HIDES AND SKINS By David G. Bailey I.???????? THEORY OF HIDE AND SKIN PRESERVATION The purpose of curing a hide or skin is to temporarily preserve it from the time it is removed from the animal until it can be processed into a final product. In the case of cattle hides the most important final product, in terms of value, is leather. By definition, curing is a temporary treatment of the hide so that microorganisms cannot break it down for food, and thus damage it. Tanning can be defined in a similar fashion because once a hide is tanned it is no longer subject to breakdown by microorganisms. However tanning differs from curing in that most tanning processes produce a permanent change in the hide that converts it into a useful product, leather. Curing is designed to be temporary so that various end products can be manufactured from the raw hide. In addition to leather, products such as gelatin, sausage casings and cosmetic ingredients can also be produced from raw hides. Whilst most tanning processes, such as chrome tanning and vegetabl