Here's a summary of a rare public paper from Pat White, then Technical Director of Tencel Ltd and writing at the time of the Lenzing takeover. It was given as the Keynote Speech at the 2004 TITK Alternative Cellulose conference in Rudolstadt Germany.
Pat White, Tencel Ltd's Technical Director reviewed 25 years spent taking the lyocell process from curiosity to reality. Charged in 1979 with developing a low cost, environmentally-friendly route to rayon which would allow the venerable viscose process to retire gracefully, he rapidly identified NMMO as the most promising solvent. Fibres made from NMMO were all but indistinguishable from the premium Japanese polynosic rayon in character, so the key developments were to devise a highly efficient recovery system for the expensive solvent, and to optimise the process to deliver acceptable throughputs despite the solvent's tendency to degrade cellulose explosively if pushed too hard. The success of the engineering development coupled with a strong fashion-led Japanese demand for fibre led to rapid expansion and Lenzing's entry into the technology. The result: excess capacity because the projected long-term increase in fashion-sales proved unsustainable. Fibrillation and its control has dominated process and market development from the start:
|Pat White leaving TITK with a present from TITK|
Currently, lyocell sales of ~90,000 tonnes/year are equally split between nonwovens, standard fibre in textiles and cross-linked fibre in textiles, with disposable wipes being the biggest single market. For the future, Mr White foresaw: