Soaking in caustic soda
In this process the wood pulp is soaked in sodium hydroxide to produce soda cellulose which is squeezed to remove the extra caustic soda solution .
The crumbs of soda cellulose are shredded to produce small flakes.
In this process, the shredded soda cellulose is aged for a certain time to adjust the molecular structure.
The aged cellulose is mixed with carbon disulphide to produce by chemical reaction xanthate
The xanthat is dissolved in sodium hydroxide to produce xanthate solution for spinning.
De-aeration and filtration
In this process, the xanthate solution is stored in tanks under vacuum to remove any air bubbles, and is passed through multi stage filters to remove any trash particles, and whenthe viscose solution is ready for extrusion after a period of ageing, it is pumped to the extrusion spinnerettes
Viscose solution is pumped to the spinnerettes, which are Immersed in dilute sulphuric acid bath, and when the solution emerges it reacts with the acid and is solidified to a continuous filament that is subjected to stretching and wound inside a rotating pot to form the viscose yarn package.
The viscose yarn packages are scoured and washed to remove residual salts and acid.
The finished viscose filament yarn is then wound on winding machines to the required forms of packages.
Scouring and crimping
This process(for filament tows) is especially for the production of viscose fibers, and is carried out on a separate production line, where the tows of continuous filaments coming out of spinneretts, are collected scoured, washed, crimped and dried.
Cutting and pressing
At this stage a layer of viscose crimped filaments transforms the filaments to fibers with length similar to cotton or similar to wool. The resulting fibers are pressed into bales as final product.