| Résumé : |
In investigating the efficiencies of unhairing agents it is necessary to ascertain the effects on the old club hairs, the short undergrowth of young hairs, the follicles and the malpighian layer. These structures and the interfibrillary matter, which consists of albumins, globulins and mucoids, are affected by the times which elapse between the death of the animal, flaying and curing as well as by the methods of curing, and soaking.
The methods of Ioosening the hair by liquid air, warm water, bacteria, enzymes, alkaIine solutions, alkaline solutions with reducing or oxidising agents, acids and lyotropic salts arc discussed and compared with the methods of tightening the hair with bactéricides, moderato concentrations of caustic soda, acid solutions such as pickles or bran drenches, protein precipitants and increasing or decreasing the moisture content in the case of the woolskins.
Microscopie observations show that the unhairing agents all act on the malpighian or soft inner mucous layer. The crux of the unhairing problem is therefore to weaken or partially dissolve the mucous layer of the epidermis and to find a machine which will remove the longer hair and the undergrowth of short young hairs. The soft inner mucous layer is rich in mucoid material. It is still considered that unhairing and bating are in essence the partial removal of this material.
In the application of modern scientific researches to the practice of leather manufacture it must be realised that science is dynamic and not static. In any particular field, the scientist has established certain facts and is investigating a number of possibilities. We must be careful to confine our thoughts to the application of established facts and remember the conditions of time, temperature, concentration, movement and degree of aeration which are inherent in these facts. Conclusions for fresh skins do net necessarily apply to salted ones. Again, precision must be used in visualising the processus of leather manufacture. This is by no means as easy as it might appear to die uninitiated for the smallest details are often significant. |
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The methods and mechanism of unhairing in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 100, N° 2 (03-04/2016)
