ASSESSMENT OF THE CAPABILITY OF LEATHER FOR FOOTWEAR UPPER TO KEEP THE SHAPE AFTER MOLDING

Abstract

The  influence  of  the  processing  conditions  of  leather  for  upper  to  keep  the  shape  after molding by the example of leather for uppers made from pigs' skins using different (vegetable, dialdehyde, syntan, chrome) tanning methods was studied to simulate the process of molding and process of keep the shape after molding on a last under real production conditions. In order to achieve this purpose, the following methods had been use in the work: organoleptic  assessment  and  physic-mechanical  analysis  of  leather,  the  molding  of  the  upper,  statistical processing  of  experimental  data.  The  molding  and  the  keep  of  shape  after  molding  was performed  on  a spherical dome (hemisphere) of the plastimetric device. To assess the molding and the keep the shape after molding  of  uppers,  the  ratio  of  the  hemisphere  radius  of  the  molded  material  sample  to  the  hemisphere radius of the same sample was chosen as a criterion immediately after strain, then after one and seven days. Results. It was established experimentally that, regardless of the manufacturing conditions (tanning method) of the leather, the molding and the keep the shape after molding of this material, all the samples change their shape compared to the hemisphere shape of the plastimetric device. The best keep the shape after  molding  is  achieved  by  heat-setting  molding  of  moistened  leather  materials  of  the  chrome  tanning method  (92%);  slightly  lower,  although  at  a  sufficiently  high  level,  keep  the  shape  after  moulding  is demonstrated by the skins of others — synthetic, vegetable, and dialdehyde — tanning methods (82, 83, and 89%, respectively). Scientific  novelty.  The  influence  of  the  conditions  of  manufacture  (method  of  tanning)  of  natural leather  materials  and  the  molding  of  the  upper  from  them  on  the  keep  the  shape  after  moulding  was
established. Practical value. According to the results of the study, it was found that when molding the upper to ensure  high  technological  properties  of  natural  leather  materials  obtained  from  pigs  using  the  tanning methods considered, the skin must first be moistened at least by 5% and then fixed at surface temperature 80 ° C for at least 1 hour: it is under these conditions that high-quality molding of the uppers.