Friday, November 14, 2014

Research Authorised and Development begins (1979)

On 4/10/79 a meeting took place in DF&VL "to decide whether to recommend that R&D work on alternative solvents for cellulose should be started".  Mike Welch (Head of DF&VL), Roger Lund (Deputy Head), Bill Brook (Head of Patent Dept), Jeff Branston, Fred Weymouth, Andy Hopkins, Dennis Woodward and Pat White were present.  If the answer was yes, then this group would decide the aims of the work and identify key areas to start.

At this meeting, the vulnerabilities of the viscose process versus a successful non-polluting solvent spinning development were listed as:
  • Pollution and hazards.  Tightening environmental legislation would, if changes were made to comply, increase the costs of viscose by around 10p/kg in the USA, rather less in Europe.
  • High spinning chemicals and recovery costs.
  • High capital costs.  The US costs for an automated viscose plant using the latest technology would be 40% higher than a new polyester staple plant.
The combined chemical consumption, services and pollution control costs for any future viscose plant would be about 3x those of Courtaulds solvent spinning processes making acrylic and cellulose acetate fibres.

The wording of the conclusion was revealing: "if a recoverable solvent system could be found for cellulose it would be a serious threat" [to Courtaulds' viscose business]

Three potentially viable competitors for viscose were listed:
  • The cuprammonium cellulose process where recent advances in ion-exchange solvent recovery had reduced energy costs and improved the viability of the technology.
  • The ITT Rayonier DMF/N2O4 was too expensive by the published route due to solvent recovery difficulties.  However if Dupont's process for making anisotropic solutions with 30% cellulose content could be applied instead of ITT's 8% cellulose route, substantial reduction in costs would result.
  • The AKZO amine-oxide process could be viable if a solvent recovery system could be developed, but it's costs were impossible to determine in the absence of any practical experience.  (Samples of amine-oxides had been made in the lab. and proved to be solvents for cellulose.)
The meeting agreed to undertake work on each of these systems to provide better information to decide future action:
  • A range of amine-oxides would be made and screened and the most promising investigated in depth for solvent stability, potential hazards, recovery possibilities, spinning speeds, fibre properties, process costs, and capital costs.
  • The solvating power of a range of known solvents would be investigated with the aim of finding anisotropic systems capable of yielding dopes with very high concentrations of cellulose.
  • Because the cuprammonium system was showing no potential for growth, practical work would be avoided but contacts with the producers would be made to ascertain current pros and cons.
This work would be carried out by 2 graduates and would be reviewed after 6 months.

No comments: