Lenzing’s advanced technologiestransforming wood into better fibers

In the pulping process, logs are debarked, chipped, and treated in a cooking liquor. Cellulose makes up around 40% of wood substance and is separated as dissolving pulp during this stage. After washing and screening to remove residual cooking liquor, knots, and impurities, our raw pulp undergoes a totally chlorine-free (TCF) bleaching process before being transformed into pulp sheets or flakes.

What remains tells an equally important story: Residual wood constituents and cooking chemicals stay within the thin liquor, where an innovative recovery process recycles the chemicals while converting organic components into bioenergy. This produces both steam and electricity.

Lenzing’s biorefinery process ensures that 100% of wood constituents are used to produce not only dissolving wood pulp for fiber production but also biobased products and bioenergy. Biorefinery thus maximizes value on both economic and environmental levels.

Viscose fibers, first produced on an industrial scale in the late 19th century, involve a multi-step chemical process. Unlike the direct dissolution used in lyocell production, our viscose process requires a chemical reaction called xanthation before the cellulose can be dissolved.

The journey begins by steeping pulp in sodium hydroxide solution to create alkali cellulose. After aging, this material reacts with carbon disulfide in a process called xanthation. The resulting substance dissolves in lye to create a deep orange, highly viscous solution − which gives viscose its name. This solution undergoes ripening and deaeration before entering the spinning process, where it’s pressed through tiny openings into an acidic bath to form filaments. These are then stretched, cut to length, desulfurized, washed, and finished.

Modal fibers follow a similar path, but with specific modifications to the spinning solution and process settings, resulting in fibers with characteristically high wet strength.