Originally posted by gone
View Post
But to address the point at hand,
"The steps in the manufacturing of bamboo viscose are as follows:
1) Bamboo leaves and the soft, inner pith from the hard bamboo trunk are extracted using a steaming process and then mechanically crushed
2) The crushed bamboo is soaked in sodium hydroxide to produce cellulose. A common misconception is that sodium hydroxide is a harmful chemical. If used in a responsible manner sodium hydroxide has little known effect on the environment and health of workers. It is routinely used in the processing of organic cotton into fibre and is approved by the Global Organic Textile Standards (GOTS) and the Soil Association Sodium hydroxide does not remain as a residue on clothing as it easily washes away and can be neutralised to harmless and non-toxic sodium sulphate salt. A chemical used in this step that can cause nervous system damage with chronic exposure is carbon disulfide. If handled properly there are no negative side effects for humans and environment as sulphur containing by products can easily be transformed into sulphuric acid which is needed for the spinning process.
3) The bamboo cellulose is forced through spinneret nozzles (like a sieve) into a sulphuric acid bath that hardens the solution into viscose fibre threads and neutralizes the caustic sodium hydroxide to form Glauber's salt, sodium sulphate, which is used e.g. as a filler in lessive detergents. The process is the standard viscose process. This process is also used to manufacture fibres from wood pulp.
4) The fibre threads are spun into viscose yarn and rolled onto spools. According to textile classification so called bamboo is standard viscose, abbreviation CV. It has no advantages with respect to standard viscose made from wood pulp like e.g. beech or eucalyptus.
The processing of the cellulose pulp into fibre "can" be cleaner than the processing used for conventional viscose "if" a closed loop process captures and reclaims all the solvents used in the manufacturing, though this is "not" standard practice. The resulting bamboo viscose fibre is very soft to the touch."
Comment