Abstract

After reviewing published methods of shortening and simplifying the chrome tanning process, the elimination of the basification stage was chosen for further investigation. Firstly, the rates of reaction between freshly prepared solutions of chrome powder and various added basifying agents was determined. As a result of these findings, a number of bases were selected for further trials in laboratory scale tannages carried Out on hide pieces. To obtain satisfactory penetration and even distribution of chrome, a short pickle was found to be essential. However, using these short float powder tannages, the importance of hide location was found to be more marked than in a conven tional tannage and this made difficult the interpretation of the results obtained. For the final assessment, therefore, matched sides were used for com parison with a conventional system. A chemical and physical analysis of the leather was carried out in addition to a subjective assessment. All the leathers produced were judged to be commercially acceptable but the following powder systems appeared to give superior results to the conventional long float method using chrome liquor:

(i) A commercially available self-basifying chrome powder.
(ii) A mixture of chrome powder and “Whiting”.
(iii) A mixture of chrome powder, soda ash and neutral naphthalene syntan.