Polypropylene drum
The introduction of Polypropylene drums permitted the routine commercial use of a range of highly corrosive chemicals in the tanning industry, for processes such as depilation and bleaching. In spite of the cheapness of the processes, the required chemicals are too aggressive for most practical choices of metal drums. Polypropylene drums for aggressive chemical processes. Polypropylene is a semi-crystalline thermoplastic with high bonding strength, tough, stable, elastic, hard and highly abrasion- and impact-resistant. Because of its chemical and physical molecular structure, solid masses of polypropylene are highly resistant to a wide range of aggressive chemicals including  aqueous solutions of salts, acids and alkalis. Applying these characteristics to the demands of the tannery, professor Mario Serrini invented the first polypropylene drum in the 1990s and subsequently he exploited the attributes of the material to refine the technical advantages and performance of the tanning process. Relevant polypropylene attributes. The typical features of Polypropylene-Homopolymers (PPH) sheets used for construction of drums include: Applicability of polypropylene drums to tanning processes. Polypropylene drums have proven suitable for innovative processes and adaptable to traditional ones. In particular: Despite the advantages of oxidative liming (cleaner, finer grained product, reduced environmental pollution, lower  costs, improved safety), oxidative liming was not hitherto practical on an industrial scale because of the effects of the chemicals on the traditional drums of wood or stainless steel.