Influence of morphological features of ostrich skins and tanning methods on the properties of semi-finished leather
The work is devoted to the study of the influence of the structure of ostrich skins and tanning methods on the performance characteristics of semi-finished leather products, to ensure its competitiveness in the domestic consumer market. In recent years, ostrich skins have been very popular for the production of a wide range of footwear, clothing and haberdashery goods. However, the existing technical solutions for the processing of this type of leather raw materials do not fully take into account the peculiarities of the texture and morphometry of ostrich skins, as well as the methods of their processing, which ultimately reduces the quality of the finished leather. The importance and relevance of this study is dictated by the need to develop scientifically grounded approaches to improve the technology of obtaining semi-finished leather products from ostrich skins with high quality indicators. The object of the study was ostrich skins covering the lower part of the bird's legs - shank (hypotarsus). It is shown that the skin has a different contour depending on the tanning method. The dermis of the tarsus is characterized by a dense arrangement of bundles of collagen fibers without subdivision into layers, the subcutaneous fat is poorly developed. When developing technological parameters for obtaining a tanned semi-finished product, chrome and combined tanning methods were used. The maximum value of the welding temperature of the semi-finished product (93-109 ºC) was obtained by tanning with chromium compounds. With the chrome-synthesized tanning method, the welding temperature was 77.0-89.7 ºC. A high index of strength (78.9±1.7 MPa), with a relatively small elongation at break - 25.7±1.2 % and low plasticity, is determined for a semi-finished product obtained at the maximum consumption of chrome tanning agent (1.5 %). It was found that an increase in the consumption of synthetic tanning agent from 1.5 % to 2.0 % does not affect the strength characteristics and lengthening of the semi-finished leather product. The index of breaking stress of the samples was determined significantly more at the consumption of the tanning agent of 2.5 %, without reducing their elastic-plastic properties.