Saturday, January 5, 2013

Geoffrey Owen's Tencel lyocell history extracts (part 2)

Geoffrey Owen of the Department of Management, London School of Economics presented a paper at SPRU in October this year entitled "Innovation in the man-made fibres industry: corporate strategy and national institutions." It is based on unpublished material made available to the author by Akzo Nobel, Lenzing and Courtaulds (amongst others) and is available in full here on the web as a PDF file.  It contains excellent sections on Tencel lyocell development history, the second extract of which is reproduced below:

Courtaulds and Tencel
Courtaulds was aware of what American Enka had been doing and their researchers saw that the solvent spinning process, if it could be made to work, might have important advantages. In 1979 a research team was set up in Coventry under Pat White, who had earlier worked on carbon fibre, to examine the process in detail; the programme was subsequently called the Genesis project. Although Courtaulds was under financial pressure at that time and several research programmes were cancelled, senior managers could see that the new process might be a way of reinvigorating the cellulosic fibres business (see Appendix 2 for a description of the solvent spinning process.)
The first laboratory-scale production began in 1981, and it was scaled up to a small pilot plant in 1983.  A note to the Board from the research department commented that the process looked extremely promising “in the sense that we believe it should be possible to produce a fibre with properties superior to viscose at lower cost…If we can succeed, this project could confound the conventional wisdom that there will be no new high volume fibre before the end of the century. It offers the possibility of transforming the prospects of our cellulosic fibre business”.

Courtaulds hired American Enka’s former research director, Bill Mathis, as a consultant. He confirmed that Courtaulds had taken a different approach to that taken by Enka and had solved some of the scaling-up problems. Courtaulds subsequently decided not to acquire an American Enka licence; it was regarded as expensive and unnecessary since White and his team were making good progress without it. Yet there were still many technical issues to be resolved.  One was to achieve a high recovery rate for the solvent which was much more expensive than the chemicals used for viscose. Another was to find a stabiliser to prevent the solvent from degrading and discolouring the cellulose. There were also difficulties in developing machinery that could dissolve the cellulose in a reliably continuous way. The published Enka route using extruders proved unsuitable for volume production. Courtaulds found an alternative route, using a Kraus Maffei horizontal mixer, and this was used in the pilot plant. It was later discovered that a more suitable machine was a vertical mixer, known as a filmtruder.

(more to come)

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