Closed Loop Production – How Lyocell Is Made

Short answer: Closed loop means exactly that: a closed circuit. The solvent used to turn cellulose into lyocell fibres is collected and reused again and again – typically more than 99 percent of it. That makes the lyocell process considerably cleaner than classic viscose production, where more chemistry escapes.

What happens in a closed loop?

Cellulose from bamboo or wood, for example, is dissolved in an organic solvent, pressed through nozzles into fibres and spun into yarn. Instead of sending used chemistry out, the solvent is cleaned and reused in the same factory. The loop is not 100 percent tight, but the loss is minimal.

Closed loop vs. classic viscose

Traditional viscose uses several chemical steps and has historically had larger emissions – although modern factories have become markedly better. Lyocell was designed for the closed loop from the start. You will find the full comparison in bamboo lyocell vs. bamboo rayon.

Why should you care?

Because the process determines a large part of the environmental footprint of your clothes. The raw material can be as renewable as you like – it only really counts once the chemistry is handled properly. Read the honest walkthrough in the guide to bamboo viscose and the environment, and experience the end result in soft bamboo bedding or bamboo underwear for men.

Frequently asked questions

What does closed loop mean in textile production?

That chemicals and solvents are collected, cleaned and reused in the factory instead of being released – a closed circuit.

How much of the solvent is reused in lyocell production?

Typically more than 99 percent. The loop is not completely tight, but the loss is very small compared with classic viscose production.

Is closed loop produced fabric better for the environment?

The process releases considerably less chemistry. The overall accounts still depend on energy, dyeing and transport, though.