In the mid-seventies the rising influence of the US anti-pollution lobby motivated several US cellulose research groups to renew efforts to find alternatives to the xanthate dissolution route. Chief among these was ITT Rayonier and it was their publications which stimulated a review of the new possibilities. This was done in Courtaulds Development Fibres and Viscose Laboratory (DFVL) - the new name for what had been the Viscose Research Laboratory (VRL) in Coventry.
Brian Gardner's August 1976 File Note entitled "Solvents for Cellulose and their Application to Film and Fibre Production - A Literature and Patent Survey." reviewed the available routes but made no attempt to evaluate their suitability as a commercial alternative to xanthation.
Mike Summers-Smith extended Brian's survey in early 1977 and added conclusions on how useful these processes might be. He listed the disadvantages of the viscose route as identified by ITT Rayonier as:
- High levels of air and water pollution. Viscose uses strong acids, alkalis, CS2 and its regeneration liberates H2S. (Mike noted that none of these pollutants need be emitted from the plant and all chemicals could be efficiently recycled given a high enough capital expenditure and energy outlay. However this would render the fibres uneconomic compared with cotton and the new synthetics.)
- High capital costs. The lengthy process with critical ageing times for alk-cell and viscose, coupled with dilute polymer solutions and slow wet-spinning processes made viscose plants fundamentally expensive.
- High energy consumption. Major advances in energy conservation were unlikely.
- High labour costs. (However the new automated viscose plants with slurry steeping, belt mercerising, wet-xanthation, backwash filters and continuous deaeration were bringing this under control).
- Increasing raw material costs, but these could be limited by increased recovery.
The new processes were divided into 4 classes according to the chemistry involved i.e. cellulose behaving as a complex or as a derivative, as a base, or as an acid.
