75 Years of Lenzing Fibres (2013)

The Lenzing website now provides a version of Tencel development story containing the following paragraphs:

On the Cover:
Lenzing succeeded in helping the viscose technology which is already 100 years old to reach new heights. At the same time Lenzing developed a completely new technology, Tencel(r), which will also shape the cellulose fibre industry in the coming 100 years.

Inside:
As of the 1970s the global cellulose fiber industry began searching for alternative production processes for viscose fibers. The most successful results were attained by researchers at the Dutch Akzo Group. After years of research work, its subsidiary American ENKA managed to dissolve pulp in the organic solvent N-methylmorpholine oxide, in short NMMO, and to produce fibers from this solvent. Akzo-ENKA operated a pilot plant using this process. The company patented its know-how but terminated any further development work.

Later these fibers were given the generic name “lyocell“.


Lenzing also carried out research on alternatives and ultimately came across the NMMO solvent process. After Lenzing had successfully manufactured fibers on a small scale using this technology, it licensed the know-how from Akzo in the year 1987.

Lenzing’s competitor Courtaulds also acquired an Akzo license.

In 1990, Lenzing started on construction on a semi-commercial pilot plant.

No company with the exception of Lenzing has decades of experience with the technology for TENCEL®, the fiber of the 21st century. TENCEL® remains the research and development priority of Lenzing. It is essential to further discover, spread and commercialize the extensive potential applications of the TENCEL® technology.

Here's the link to the relevant pages.  

While Lenzing continue to gloss over the Courtaulds contribution to Tencel development*, the new history is commendably candid about the Third Reich origins of their viscose operation:

Solvent Spun Rayon: Prof Turbak's view of the early history (Part 2)

The second extract of Prof. Alban Turbak's chapter on dissolution of cellulose:

Other Cellulose Solvent Systems
In each and every instance of dissolution of cellulose ... thermodynamic factors can be delineated and shown to have a significant and controlling effect on the success of the dissolution process.  In each case the solvent system swells the cellulose and then modifies the molecule either by derivatizing, proton weakening or removal, or by  complexing, to give  a new intermediate specie that can more readily react with the liquid solvent system.

Thus, all cellulose solvent systems can be categorized under 4 mechanisms:

a)    Cellulose as an acid

b)    Cellulose as a base

c)    Cellulose unstable derivative

d)    Cellulose stable derivatives

                                                                                                                

This chapter will review selected solvent systems involving  areas a, b, and c. Stable derivatives (d) will not be discussed.  All compounds can be considered to be acids or bases relative to some other stronger specie. For example;

       (A) is an Acid      relative to       Base  (B)

       HCl, ­­­H₂SO₄                              Carboxylic Acids

       Phosphoric                              Acetic, Cellulose

       Phenol                                     NaOH, Sodium Carbonate

       Alcohol                                   NaOH, sodium Metal

       Cellulose                                NMMO, N₂N₄

       Li⁽⁺⁾/DMAc                              Cellulose

      Cellulose-OH                           Unsolvated  anhydrous Cl^(-)

      Hydrocarbons,(isobutane)           NaNH₂

It may seem odd to realize that cellulose can act either as an acid or a base, yet this is exactly the case; especially in anhydrous or limited aqueous systems .

Water is an excellent swelling liquid for cellulose and opens millions of internal pores  in the cellulose  microfibrillar structure .  However, H₂O is itself both an acid or a base depending on the other molecular specie. Therefore, water normally reacts more rapidly than the cellulose with incoming molecules and this totally disrupts the effectiveness of the incoming potential dissolving moiety.

See Also  "Solvent Spun Rayon" and "Regenerated Cellulose Fibres"

Solvent Spun Rayon: Prof Turbak's view of the early history (Part 1)

Prof. Alban Turbak did ground-breaking work on the dissolution of cellulose during the 1970's while with ITT Rayonier.  As he mentions in this extract of his introduction to non-NMMO cellulose dissolution methods in Regenerated Cellulose Fibres, his 1977 "Solvent Spun Rayon" book  provided one of the stimulii for research work to begin at Courtaulds.  His definition of these fibres as "reconstituted" rather than "regenerated" no longer figures in the nomenclature.

Ever since the discovery of the xanthate process by Cross and Bevan in 1892 and its commercialization in the early 1900’s there have been many efforts to dissolve cellulose directly in non-aqueous solvents which would be both easy to use and readily recoverable. The viscose process produces good quality films and fibers. However, by the mid 1970’s pollution problems and price competition from synthetic films and fibers had seriously eroded the cellophane and rayon markets. In order to remain commercially competitive it was necessary for rayon and cellophane producers to seek simpler less polluting processes.

In the mid 1970’s I.T.T. Rayonier decided that to preserve their pulp markets it would be in their best interest to take the lead in trying to find new ways to make rayon. To their credit, Rayonier’s management authorized a multi-million dollar research effort which ran for a period of 7 years at the I.T.T. Rayonier Eastern Research Division Laboratories. The overall goals were to develop new direct cellulose solvent systems which would require lower investment costs and be readily recovered and recycled in closed loop non-polluting systems.

In order to identify potential previously examined solvent candidates an extensive literature search was made covering 80 years of cellulose solvent reports A close examination and evaluation of these reports from a physical organic viewpoint led to a review paper which, for the first time, delineated all cellulose solvent systems into four simple categories.(1) Subsequently, several other solvent system reviews have been reported (2,3) Rayonier reported some of their preliminary results at an American Chemical Society symposium in New Orleans in 1977.(4) As a result of Rayonier’s stimulus other companies and research universities undertook cellulose solvent research projects.

Concurrently, Franks, McCorsley and Varga at the American Enka Corp were deeply involved in evaluating N-Methyl Morpholine-N- Oxide (NMMO).(5). The Enka NMMO technology was subsequently pursued by Courtaulds in England. As is now well known, Courtaulds’ Tencel® NMMO solvent spun cellulose fiber technology is now a major commercial success and solvent spun cellulose films for food packaging are currently under intense investigation. Tencel® lyocell is actually not a regenerated cellulose fiber but, rather, is a reconstituted cellulose fiber since it was never derivatized.


1. Turbak, A.F., Hammer. R.B., et al, Cellulose Solvents, CHEMTECH, 10,51-57, Jan. 1980
2. Hudson, S.M., and Cuculo, J.A., The Solubility of Unmodified cellulose: A Critique of the Literature, J. Macromol. Sci.,18, (1) 1-82,1980
3. Johnson, D.C., Solvents for Cellulose, Cellulose Chemistry and its Applications, Ellis Harwood, Ltd., Chinchester, 1985
4. Turbak, A.F., Solvent Spun Rayon, Modified Fibers and Derivatives, ACS Symposium # 58, Amer. Chem. Soc., Washington, D.C., 1977
5. Franks, N.E., McCorsley, C.C., and Varga, J.K., U, S. Patent 4,142,913 March, 1979; U.S. Patent4,196,282 April, 1980

Geoffrey Owen's Tencel lyocell history extracts (Part 6 - Lenzing)

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 sixth extract of which is reproduced below.  This final part deals with the early history of Lenzing leading to their lyocell development.

The rayon factory in the town of Lenzing, situated in Upper Austria between Salzburg and Linz, was built in 1938 as part of the Nazi authorities’ self-sufficiency programme; a number of plants were built in Southern Germany and Austria in order to replace cotton imports. The rayon factory was adjacent to an existing pulp mill, which became the main source of woodpulp; the mill was bought by Lenzing in 1969. The integration of pulp and rayon production gave Lenzing a cost advantage over rayon producers such as Courtaulds which obtained their wood pulp from distant suppliers.

After the war the company was controlled by two partially state-owned banks, Landerbank and Creditanstalt. Subsequent mergers in the Austrian banking industry led to the creation of Bank Austria, which became the principal shareholder. Lenzing was listed on the Vienna Stock Exchange in 1985 but only about 10 per cent of the shares were offered to outside investors. Lenzing was expected to make profits and to pay dividends but it was not a shareholder-driven company. As the principal employer in its region, it had a social responsibility which influenced its strategic decisions, not least its determination to make the best possible use of the site. A drawback of the site was the lack of water and Lenzing had to invest in costly techniques to
reduce its water consumption while also meeting the environmental rules laid down by the regional government. The result was a cleaner manufacturing process, giving the company the confidence to continue improving the viscose process at a time when other producers were cutting back. 

Lenzing also developed speciality cellulosic fibres, of which the most important was modal; launched in 1964, this was a “high wet modulus” fibre, stronger than rayon and suitable for hightenacity applications.  Lenzing took a cautious approach to synthetic fibres. It made a brief foray into acrylics and later into polyester in partnership with Hoechst, but was never a major producer. Because of its limited involvement in synthetics, Lenzing was less affected than most other European fibre producers by the over-capacity crisis of the mid-1970s. At the end of that decade it made what turned out to be an important decision to participate in an Indonesian viscose plant with the Indian Ashok Birla group. The Indians had asked for technical assistance and in exchange Lenzing secured a minority interest in the new company. This plant, which started production in 1982, gave the Austrian company a foothold in a region where demand for man-made fibres was growing fast, and paved the way for subsequent investments in Asia; Lenzing later acquired majority control of the Indonesian company.

Like Courtaulds, Lenzing was aware of possible alternatives to the viscose process and it initiated research into solvent spinning during the 1980s. A pilot plant was built in 1990 and five years later Lenzing decided to manufacture its own lyocell fibre, a direct competitor to Tencel; production began in 1997. In 2004 Lenzing bought the ex-Courtaulds Tencel business from CVC.This added the two Tencel plants which Courtaulds  had built, in the UK and the US, to Lenzing’s existing plant in Austria. All three factories were subsequently expanded, and in 2010 Lenzing announced plans to build a new Tencel plant in Austria. The Tencel takeover was one of a series of moves which gave the Austrian company a more international dimension. The Indonesian plant was enlarged and in 2005 the decision was taken to build a viscose plant at Nanjing, China; another Asian viscose plant, in India, is expected to come on stream in 2013. Lenzing is now one of the two leading producers of cellulosic fibres, the other being the Aditya Birla group in India. Nearly 60 per cent of its sales come from Asia, but the heart of the company remains the original site in Lenzing; some 3,000 out of the company’s total labour force of 6,600 are employed there. 

Although Lenzing has diversified on a small scale outside fibres, principally in plastics, its strategy since the war has been based on the belief that, with continuous investment in new technology and new product development, cellulosic fibres will remain a good business to be in. This consistency has been reinforced by the company’s ownership structure. In 2000 Bank Austria sold its shares to an Austrian foundation, the B & C Private Foundation, whose mission was to act as a long-term core investor in Lenzing, with a commitment to maintain the company’s role in the Austrian economy. In 2011, as part of a capital reconstruction which involved the issue of new shares, B & C reduced its share of the voting shares to 68 per cent and the free float was increased to about 33 per cent.  Part of the motivation was to make Lenzing shares more accessible to international investors. 

Geoffrey Owen's Tencel lyocell history extracts (part 5)

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 fifth extract of which is reproduced below.  This deals with the early history of Courtaulds putting the Tencel development in context.  The final extract will do the same for Lenzing and their lyocell.


Founded in 1816, Courtaulds became one of the country’s leading silk weavers, but by the end of the century its main product – mourning crepe – was in decline and new sources of growth were needed. In 1904 it acquired the patents for the viscose process. A factory was built in Coventry, and over the next few years Courtaulds established itself as the world’s leading rayon producer. It was the first European company to start rayon production in the US; its American subsidiary accounted for a large share of its profits in the inter-war years.  

Following the invention of nylon, Courtaulds was eager to get into synthetics, and in 1940 it formed a joint nylon venture with ICI. (ICI had a patent-sharing agreement with DuPont and thus had access to the American company’s nylon technology.) However, it was kept out of polyester by ICI, which was the principal patent holder, and although Courtaulds launched its own acrylic fibre, Courtelle, in 1959, it was still heavily dependent on slow-growing cellulosic fibres. Partly for that reason, it diversified into other industries, principally paints and packaging. It also had a small textile business, derived from its earlier vocation as a silk weaver. 

The diversification drive was stepped up in the mid-1960s, following an abortive attempt by ICI to take over Courtaulds. The new management which took control of the company after the bid adopted a policy of forward integration, investing on a large scale in textiles and clothing in order to secure captive outlets for its fibres. The company also made further acquisitions outside fibres, principally in paints. A new business that was started in the 1960s, based on licensed technology, was carbon fibre, which is described more fully in the next section; carbon fibre later formed part of a new division, Courtaulds Advanced Materials.

The investment in textiles and clothing proved to be a serious mistake and in the mid-1970s Courtaulds was in financial trouble. Many of its textile mills and clothing factories could not compete with imports from low-wage countries; cutbacks in capacity were unavoidable. In fibres Courtaulds had been successful with Courtelle but still had a big commitment to cellulosics, the outlook for which looked unpromising. Of its various diversifications only paints had done well. 

What followed in the 1980s was an attempt to reposition the company, aimed at businesses in which Courtaulds had, or could reasonably hope to create, a competitive advantage. Textiles and clothing were demerged into a separate company, Courtaulds Textiles; several downstream chemical businesses, principally in coatings and advanced materials, were acquired; and a
woodpulp mill in South Africa which had been the principal supplier to Courtaulds’ rayon factories, was sold. Fibres might have been divested during this period, but Courtelle was profitable, and the company had developed a new cellulosic fibre, based on the solvent spinning process (see below),
which appeared to have excellent prospects. In 1990 the company decided to manufacture the new fibre, branded as Tencel, in the US; the factory came on stream in 1992. 

By the mid-1990s Courtaulds had two main businesses, paints and fibres, of roughly equal size and at this point the company’s financial position began to deteriorate. Profits from the older fibres had collapsed, while sales of Tencel, after a promising start, were slowing down. Several of the acquired businesses were performing poorly. The best part of the company was the paints division, and it attracted the attention of international paints companies which were seeking to enlarge their stake in this industry. In 1998 Akzo Nobel, the Dutch company, launched a successful takeover bid for Courtaulds. Its only interest was in paints; the fibres business, including Tencel, was later sold to CVC, a private equity firm.

Geoffrey Owen's Tencel lyocell history extracts (part 4)

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 fourth extract of which is reproduced below:

When the plant came on stream in 1992, much of the initial demand came, not from the US, but from Japan. The Japanese textile industry, looking for profitable niches in the market to offset the loss of commodity business to imports, found that the fibrillating characteristics of Tencel could be used to produce high-quality fabrics, principally denim, with an unusual peach-like texture, and customer reaction was enthusiastic. With the aid of an Osaka-based consulting firm, Courtaulds organised a club of spinning, weaving and finishing companies, chosen on the basis of their technical and commercial competence and their willingness to invest in the machinery needed to process Tencel efficiently.

Although Tencel was sold in Japan as a premium fibre, its success there suggested that the textile qualities of the new fibre would be more important than had been predicted when the Mobile plant was approved The McKinsey study had forecast that the main demand would be industrial, with apparel acting to some extent as a filler. The change of emphasis was expected to work to Courtaulds’ advantage, since the apparel market offered higher margins and should be quicker to develop than the industrial market; extensive testing would be necessary before Tencel could be used, for example, in medical applications.

Looking further ahead, senior executives in Courtaulds believed that, as the

Geoffrey Owen's Tencel lyocell history extracts (part 3)

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 third extract of which is reproduced below:

The first Tencel plant

Meanwhile, Courtaulds had been pushing ahead fast. The pilot plant in Grimsby had worked well, and there was no doubt in the minds of Tencel’s supporters that the next step was to build a full-scale plant, either at Grimsby, next to the existing acrylic fibre plant, or at Mobile, Alabama, which was the site of a Courtaulds rayon factory. The case for going ahead was that Courtaulds had a technical lead in a product that not only had distinctive properties as a fibre but was also the only man-made fibre that could be produced from renewable resources by an environmentally friendly process.

When members of the Group Executive considered the proposal in April, 1990, they had before them a study from McKinsey, the management consultants, which supported the project. According to McKinsey, there would be sufficient demand, initially in industrial rather than textile markets, to absorb the output of the first plant at an acceptable price. Tencel’s high wet strength and absorbency would make it very suitable for wipes and other disposable products. One member of the Executive was doubtful, on the grounds that Tencel was a high-risk project with an uncertain payback. He acknowledged that Tencel was a potentially attractive fibre with some advantages over viscose, but it was not as novel or distinctive as polyester and nylon had been when they were introduced and sales projections were bound to be speculative. Spending on Tencel would absorb cash at a time when Courtaulds was trying to expand in non-fibre industries. In his view alternative strategies for Tencel should be considered, including partnership or licensing.

Despite these objections the majority of the committee took the view that Tencel was too good an opportunity to forgo. Apart from the merits of the new fibre, the project had the attraction of being based on in-house research and linked to Courtaulds’ long-established expertise in cellulosic fibres; it should be less risky, and less difficult to manage, than an acquisition. The initial plan was for the plant to be built at Grimsby, and the company hoped to get a government grant to support this investment. When the application was turned down, attention switched to Mobile. The state of Alabama was keen to attract the project and willing to offer financial support. The proposal was approved by the Board and the ground breaking ceremony at Mobile took place in September 1990. Production was scheduled to start in the summer of 1992, with an initial capacity from two production lines of 18,000 tonnes a year.

(More to come)

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)

Early Tencel History from "Regenerated Cellulose Fibres"

Regenerated Cellulose Fibres published by Woodhead Publishing Ltd in 2001 contains a history of the Tencel development, the first extract of which appears below. (see the original for references)

Direct Dissolution in Amine Oxide: Lyocell

Lyocell technology was pioneered in the USA by Eastman Kodak and American Enka, but it was Courtaulds in the UK who persisted with development until a commercially viable fibre process emerged. Furthermore, Courtaulds did it at a time in its history when the very wisdom of continued involvement, not just in cellulosics but in any fibre or textile activity, was being called into question.

As early as the mid 1950's, Courtaulds believed the future of viscose to be so unattractive that it started to divert viscose profits not only into other fibres, but also into totally unrelated businesses.

By the late fifties, despite accounting for 80-90% of Courtaulds earnings, the reality of viscose's decline was becoming apparent. The usual remedies, reducing costs, improving quality, selling more aggressively and internationally were yielding diminishing returns so the Board's reaction was a new strategy involving:

• Developing new internal sources of profit i.e. utilising the viscose wet-spinning expertise to move into wet-spun acrylic fibres ("Courtelle"), and opening up a vast, and with hind-sight, transient, new market for a coarse and tough viscose in tufted carpets. ("Evlan")
• Developing new external sources of profit by acquisitions in "related but different" products, in reality British Celanese (Cellulose acetate fibres and related products) and Pinchin Johnson Paints (Later renamed International Paint)
• Developing greater market power by acquiring key elements of the rest of the fibre value-chain - "Verticalisation" - resulting most notably in the acquisition of the Lancashire Cotton Corporation Ltd and Fine Spinners and Doublers. (representing about 35% of the entire Lancashire cotton industry.)

Of these three, a) was least favoured with funds. Furthermore, little emphasis was placed on modernisation of regenerated cellulose fibre production methods

Early Tencel History from "Regenerated Cellulose Fibres" (part 2)

Regenerated Cellulose Fibres published by Woodhead Publishing Ltd in 2001 contains a history of the Tencel development, the second extract of which appears below. (see the original for references -  click here for first extract)

NMMO emerged as the best of the amine-oxides and a team at American Enka demonstrated its commercial potential in the late '70's. In their laboratories in Enka, North Carolina, Neil Franks and Julianna Varga, developed a way of making a more concentrated, and hence economical, solution of cellulose, by carefully controlling the water content of the system.

In this Figure from USP41926282 the concentrations of water and cellulose where complete dissolution of the cellulose occurs (at 95C), lie between lines B and C. Between lines A and B there can be 95% confidence that the solution would be free from undissolved cellulose fibres, and to the right of Line A, undissolved cellulose fibres are bound to be present. Similarly, between C and D there is a 95% chance that crystals of undissolved NMMO will be present, and such crystals will always be present to the left of line D.

Clarence C. McCorsley III, also at Enka, developed the key elements of several possible commercial processes. In one, cellulose pulp sheets were soaked in NMMO solution, and after mild heat and vacuum treatment to adjust the water content, the ground-up sheet was fed to an extruder from which fibres could be spun. In another, the solution was made in a large mixer prior to casting it as thick film, freezing it solid, and grinding up into chips for later extrusion. In a continuous process, a vented extruder fed directly with the ground-up wood-pulp and NMMO, mixes the ingredients, creates the solution by removing excess water and volatiles through the vent, and feeds the spinning pumps.

Both American Enka and Courtaulds set up pilot plant work in the early eighties with the objectives of developing the fibre spinning and solvent recovery operations. Courtaulds commercialized first and this, and the continuing development of lyocell is dealt with by White , who from the outset of practical work in 1979, led the lyocell development effort at Courtaulds.

(more to come)

Early Tencel History from "Regenerated Cellulose Fibres" (part 3)

Regenerated Cellulose Fibres published by Woodhead Publishing Ltd in 2001 contains a history of the Tencel development, the third extract of which appears below. (see the original for references - click here for first extract)

American Enka decided not to commercialise the process and stopped the research in 1981, probably because at that time engineering issues associated with the difficulty of avoiding exothermic reactions looked too hard to resolve economically. However when Courtaulds had demonstrated practical solutions to the many problems discovered during American Enka's early work, they (Enka that is, now part of Akzo-Nobel) re-entered the field with the continuous filament version of the lyocell process under their brand name "Newcell". The Akzo deal with Courtaulds involved their gaining access to Courtaulds technology in exchange for granting Courtaulds rights to use some of the key steps in the early patents mentioned above.Coming right up to date, Akzo Nobel acquired Courtaulds in 1998, and formed Acordis Fibres, bringing together in one company all the key lyocell technology. However, Akzo-Nobel had earlier granted a lyocell license to Lenzing, the Austrian viscose fibre maker, allowing Lenzing to enter the field with a very similar process to Courtaulds. The ensuing patent litigation between Lenzing and Courtaulds was to prove costly to both companies.
Lenzing obtained a patent in the USA for a process, some aspects of which had been operated by Courtaulds for many years, and indeed were used in production at Courtaulds Tencel® plant in Mobile. Courtaulds naturally objected,

Geoffrey Owen's Tencel lyocell history (part 1)

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 him by Akzo Nobel, Lenzing and Courtaulds (amongst others) and a draft is available in full here on the web as a PDF file.  It contains excellent sections on Tencel lyocell development history, the first extract of which is reproduced below. The subject is also covered in his recent book - essential reading for any students of success and failure in fibre development - "The Rise and Fall of Great Companies: Courtaulds and the reshaping of the man-made fibres industry" published by OUP, 2010.

Lyocell (Tencel): Courtaulds versus Lenzing: 

Background

A disadvantage of the viscose process – and this was one of the reasons why several companies abandoned it – was that it was highly polluting. It used several toxic chemicals, most of which had to be disposed of as effluent. The search for a cleaner process, which began in the 1920s, was based on the idea that, instead of breaking up the cellulose extracted from woodpulp and regenerating it, cellulose might be dissolved directly using chemicals which would be easy to use and recover. The most promising solvent, first identified by two Swiss chemists in 1939, was an amine oxide, a non-toxic chemical, and this work was taken further after the war by Eastman Kodak in the US.

Eastman’s scientists filed their first solvent-spinning patent in 1966 but the company decided not to commercialise the process. American Enka, the US affiliate of the Dutch company Akzo, acquired the patents and made further improvements, principally in the solvent composition and in spinning. However, the company ran into problems when it tried to produce fibre on a large scale and spinning quality was poor. The Dutch parent company discontinued the work on solvent spinning and in 1985 sold American Enka to the German chemical company, BASF. The patents that American Enka had filed were put together in a manual and offered for sale.

(More to come)

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The Eastman scientist who filed the first patent on NMMO as way of making cellulose dopes was Dee Lynn Johnson who moved to 3M later in his career.  In the early 90's I was invited to give a talk on lyocell at 3M's Technical Center in Minneapolis and had the pleasure of meeting Dee, then recently retired.  He was of course delighted that his cellulose dope idea was at last being commercialised to make Tencel fibre in Mobile.