Neutralisation and Bating of Hide Unhaired Using Sodium Silicate and Sodium Sulphide

Abstract

Various methods of neutralisation of hide unhaired with sodium silicate and sodium sulphide have been investigated seeking to reduce or refuse ammonium sulphate conventionally applied for the neutralisation. Due to the high release of ammonia into the environment, alternative materials are being sought that do not impair the properties of the hide being processed and that a high-quality chromed semi-finished product of leather can be obtained. In the research, different methods of hide neutralisation and their influence on subsequent hide treatment processes qualitative indexes of the obtained leather were analysed and described. It has been found that after unhairing with sodium silicate and sodium sulphide hide, it is appropriate to neutralise and bate the hide by adding 1 % ammonium sulphate, 0.8 % lactic acid and 0.15 % proteolytic enzyme preparation OROPON ON2. To obtain the best quality of chromed semi-finished product of leather, it is advisable to pickle the hide using not more than 1 % sulfuric acid. In this way, neutralised-bated, pickled and chromed leather’s quality meets the quality requirements for chromed semi-finished product of leather.