This week, Vancouver-based paper maker Fortress Paper announced a new venture (read “Fortress Paper Announces An Acquisition To Enter The Specialty Cellulose and Bio Energy Sectors”) acquiring a mill in Thurso, Quebec with the intention of transforming wood pulp into specialty cellulose.
Derived from dissolving wood pulp to its organic core, specialty cellulose is a most often used in the textile industry for the production of rayon
So what exactly is rayon?
A Short History:
In production since the late 19th century, rayon is one of the oldest manufactured fibers in the world. Made famous around 1920 by Dupont Chemicals, rayon was predominately used by the company to make curtains.
The fabric gained a less-than-stellar reputation around this time because though it was easy to work with – and especially easy to dye – rayon was often mixed with other cheaper fibers to make cheaply made garments that didn’t stand up to heavy wear.
However, because the fiber has a high uniformity, it is very durable and frequently used as an alternative to silk, usually to produce high-end clothing items such as evening gowns and flowing garments. It is a highly absorbent fiber that breathes well, is soft and comfortable and supports vibrant colours.
The Science of Rayon:
Rayon is not a natural fiber, it is a manufactured fiber derived from naturally occurring cellulose typically extracted from wood pulp.
The pulp’s cellulose is steeped in caustic soda, which concentrates some of the cellulose into soda cellulose. After pressing, the cellulose is shredded into a substance called white crumb.
The white crumb is then oxidized, forming shorter molecular chains, and treated with carbon disulfide. The soda cellulose reacts with this substance, forming yellow crumb due to inorganic compounds that emerge during the chemical process. This yellow crumb is dissolved in a caustic solution, which relaxes the hydrogen bonds in the cellulose, producing a highly viscous substance.
This viscous fluid is allowed to age, breaking down the cellulose structures further to produce an even slurry, and then filtered to remove impurities. Small air pockets are forced out to ensure a strong, even fiber, and the mixture is forced through a spinner, which forms many even strands of fine thread that enter a setting solution to form cellulose filaments: also called rayon. The rayon is stretched to form a strong, even bond, washed, and then formed into rayon fabric.
Since rayon is a man-made fiber extracted from wood pulps its properties are more similar to cotton or linen than synthetic fibers like nylon or polyester.
Responding to Industry Demand:
Because many textile manufacturers prefer using rayon over cotton, there is an overall increase in the demand for this fiber. In the last five years, the rayon market has grown by seven per cent worldwide. Recent reports suggest that there is a current shortfall of approximately 0.5 million tonnes in the global annual supply.
In their recent press release Fortress Paper revealed that once the necessary technical conversion at the Thurso mill is complete, they expect to produce more than 200,000 tonnes of specialty cellulose annually, which the company will sell to textile markets around the world in order to manufacture rayon.