Tencel in Courtaulds Annual Reports (1981-90)

The Courtaulds Annual Reports contain concise statements of the progress of the Tencel development year-by-year.  These statements have been pasted into a series of 10 posts which can be read in sequence by scrolling down from here:

1981-82 - under "Research"

Technology is being developed in the use of novel solvents for the conversion of woodpulp to regenerated cellulose products, leading to lower effluent levels and reduced energy consumption in the manufacturing process.

1982-83 - under "Courtaulds Research"

 A pilot plant incorporating a process which directly dissolves cellulose ran successfully towards the end of the year.  First indications are that the process may provide a low cost route to novel types of fibres and films.

1983-84  - under "Courtaulds Research"

Development of the new process for directly dissolving and regenerating cellulose continued.  Samples of fibres, of fabrics made from them and of transparent films have been produced, all with interesting properties.

1984-85 - Under "Research"

The research progamme into the production of new fibres and films by direct dissolution and regeneration of woodpulp continued successfully.

1985-86 - under "Research"

The development of a direct solvent spinning system for cellulosic fibres and films continued successfully.  An expanded pilot plant will be available by the end of 1986.
1986-87 -  under "Fibres"
Research expenditure was again at a high level for all fibres, but especially in the development of the new solvent-spun cellulose fibre.  Its pilot-plant came on stream and good progress has been made on the next stage of production which will make commercial quantities available.
               - under "Research"
The programme to develop a new range of cellulosic fibres using a new direct solvent spinning system continued with the successful commissioning of an expanded pilot-plant and with engineering developments for further expansion.  The process gives significant improvements over existing fibre properties and environmentally.
1988-89 - under "Fibres"
The first commercial scale Tencel plant was commissioned during the year. Its capacity is modest and design work on larger units is now well underway.
                - under "Research"
Substantial work was undertaken to transfer expertise learned on the pilot plant...to the scaled up plant commissioned...at Grimsby.
1989-90 - under "Fibres and Films"
The new solvent spun fibre Tencel continued to progress well.

N.B.  (1) Tencel is not mentioned in the "Research and Technology" section in 89-90.
        (2) The Textiles business had been demerged and was no longer part of the Courtaulds Group.
        (3) Saiccor Pulp (the best pulp for making Tencel) had been sold in 1988 to fund acquisitions of US sealants and adhesives.
        (4) Bonded Fibre Fabric, the nonwoven business which had been modernised at the end of the eighties, was sold at the end of March.  (Tencel was showing great promise in nonwovens)
        (5) Prior to 1989-90, "Fibres" came immediately after the "Chairman's Statement" at the front of the Annual Report.   Here "Fibres" comes last after Coatings, Performance Materials, Packaging and Chemicals.  Furthermore it has been merged with the "Films" used in packaging - cellophane, polypropylene and polyethylene.  Maybe the continued development of Tencel clashed with the emerging strategy of getting out of Fibres and Textiles and was therefore downplayed.

Thanks to Ted Richards who provided the full set of Courtaulds Annual Reports from 1970 to 98

DEVELOPMENTS IN CELLULOSE SOLVENTS MEANS NO MORE NEW VISCOSE PLANTS (1984)

Many cellulose research centres throughout the world are now actively enaged in developing and studying new cellulose solvent systems and in spinning quality rayon fibres. This article compares the use, advantages and limitations of amine oxides, liquid ammonia and ammonium salt, lithium chloride with dimethylacetamide (DMAc) as three of the most recently described new solvent systems. The amine oxide and lithium chloride/DMAc systems are both cost-competitive with viscose on a greenfield installation basis. It is considered that additional work is needed to find an even more economical system with further reduced recovery and recycling costs. There is now little doubt that any further rayon production will not involve the viscose process and that some form of recyclable solvent system will be employed.

Turbak A F,. Tappi J., vol. 67, no. 1, Jan. 1984, pp 94-96

Al Turbak was not alone in thinking that new viscose plants would never again be built.  The rayon market was shrinking and viscose plants were closing at this time.  30 years later it was evident that viscose technology was preferred to solvent spun (lyocell) technology by the then leading exponent of both - Lenzing.

It is interesting to see that Al felt something more economical than NMMO would be needed for success.

Mike Perry recalls Pat White, Buffer tanks and Jets. (circa 1984)

I was the engineer responsible for the construction of the pilot plants built in the ASF Lab. I remember working with Pat White the major driving force on the project. Without Pat I’m sure that Tencel would have remained a laboratory curiosity. I think we started off with a mutual distrust of each other but as our working relationship continued this grew into respect. I admired his abilities very much and his willingness to experiment..

The two things which pleased me most that I designed was the buffer tank and the beam spinning jet.

The buffer tank solved the problem of maintaining a supply of dope to the spinning jet pump at constant pressure with a variable flow coming into it. It also had a system of first in – last out to minimise stagnant volumes of dope within the tank.

With the spinning jet design I realised that the relatively new process of electron beam welding could be used for constructing jets with a rectangular shape. The cleanness and precision of the process meant that the jet plates could be perforated before welding into the body of the holder. A small jet was made first that would fit the standard round holder to try out the principle and check the distortion of the jet plate when subjected to the high pressure when in use. From the data obtained the dimensions of the beam jet with multiple rectangular jet plates  could be worked out. The hole layout and form was done by others. I remember that the jet hole had to be parabolic in section so there was no sudden change in acceleration of the jet stream which would cause the formation of droplets. I used the formula for the design of pressure vessel flanges for the closure of the beam jet. This gave a rather bulky and heavy form. When CEL took over the design for the Grimsby plant they reduced the size of bolts and flange thickness on their design. It leaked under pressure. I’m ashamed to say I felt a little smug! This design of spinning jet was patented.

Dimensions of jet from my notebook probably done at a meeting to discuss requirements,

I hope this diatribe gives you some more background to the Tencel story although perhaps not worthy of a blog.

Cheers

Mike.