Optimum chrome tanning of hides and modified Thrublu process for lime-split hides

摘要

Chrome tanning for a long time enjoyed a unique position amongst tanners all over the world and almost 90% of leather produced is chrome tanned. Of all these benefits, high shrinkage temperature has been the paramount feature in favour of chrome tanning as this cannot be achieved by any other tanning systems. A number of studies have been published recently suggesting that Chromium(Ⅲ) itself may be toxic at higher levels under certain ligand environment and Chromium(Ⅵ) is a known carcinogen. So, tanners have to consider how best to modify their chrome tanning process for better exhaustion of chrome and look for alternative means to minimise the impact of tanning on the environment. LASRA research has shown that none of the alternatives to chrome free tanning systems are as cost effective and cheap than chrome tanning. The best commercial option is, therefore, to develop an effective chrome management system for the tannery. Several chrome management technologies have emerged recently. Among the options available is the no pickle ThruBlu process, first introduced for lambskins in 1993 at LASRA Conference by DasGupta and further developed and subsequently extended to split hides tannages. It is is the most cost effective and easily adoptable. But this novel system challenges the basic established theory of chrome tanning and therefore demands conviction from tanners. The partial substitution of chromium with alternative tanning agents like Oxazolidine E (Zolidine E, Angus Chemicals), THPS (Albrite AD, Rhodia) is also promising because this combines benefits of both the tanning materials.