Lyocell

Lyocell emerged as the sustainable alternative to viscose rayon—a regenerated cellulose fiber produced without the toxic carbon disulfide that made conventional rayon production hazardous to workers and environments. Courtaulds developed the fiber under the brand name Tencel through the 1980s, with a 25-ton/week semi-commercial production line opening at Grimsby, UK in 1988. By 1993, full commercial production was underway, after Courtaulds had invested £100 million and ten years in development.

The adjacent possible for lyocell opened through a different solvent. The viscose process, invented in 1891, dissolved cellulose using carbon disulfide—effective but toxic. Researchers sought alternatives for decades. In 1966-1968, D.L. Johnson at Eastman Kodak studied N-Methylmorpholine N-oxide (NMMO) as a cellulose solvent. American Enka at Enka, North Carolina developed the basic lyocell process in 1972 but couldn't commercialize it successfully. A 1981 patent by Mcorsley for Akzona described the NMMO dissolution process.

Courtaulds Fibres in the UK took the concept and solved the engineering problems. A 100-kilogram/week pilot plant opened in Coventry in 1982; production increased tenfold to a ton/week in 1984. The critical innovation was the closed-loop solvent recovery system: more than 99.8% of the NMMO solvent could be captured and recycled, eliminating waste and dramatically reducing environmental impact.

The production process was elegantly simple compared to viscose. Wood pulp was dissolved directly in NMMO (no chemical derivatization required), pumped through spinnerets into a water bath where the cellulose regenerated as fiber, then washed, dried, and baled. The closed loop meant the solvent was recycled rather than discharged. The fiber itself biodegraded without harmful byproducts.

Courtaulds opened full-scale commercial production at Mobile, Alabama in 1990 and at Grimsby in 1998. In 1998, Akzo Nobel acquired Courtaulds, eventually selling the Tencel division to Lenzing AG in 2000. Lenzing combined Tencel with their own lyocell business and by 2015 was producing 130,000 tonnes annually—the world's largest lyocell producer.

The cascade from lyocell reshaped sustainable textiles. Fashion brands seeking alternatives to petroleum-based synthetics and water-intensive cotton adopted lyocell for its sustainability credentials. The fiber appeared in everything from casual wear to luxury fashion. By 2024, lyocell had become a mainstream sustainable fiber option, with Lenzing's Tencel brand recognized globally.

Lyocell illustrates how environmental constraints can drive innovation. The search for an alternative to toxic carbon disulfide led to a fundamentally cleaner production process. What began as pollution prevention became a competitive advantage as consumer demand for sustainable materials grew.