The Forest Scribe

FACT SHEET – Wood Product: Rayon Viscose

What is Viscose Rayon?

  • It is a textile material made of yarns that is the product of cellulose regeneration
  • Viscose Fiber is made by dissolving wood pulp and regenerating it in the form of fibers
  • The yarn is made of an organic polymer that contains the chemical elements of carbon hydrogen and oxygen
  • Is as semi-synthetic fiber that cannot be categorized as natural nor synthetic
  • The yarn is produced by spinning the viscose into rayon which then are used to produce a smooth textile that does not get easily wrinkled
  • The resulting textile has a high sweat absorbing capacity that is just as with cotton cloth
  • Its main characteristics include breathability, ease in dying and being colorfast, easy and cost-effective manufacturing and its high versatility in production and use

 

What are the Main Ingredients of Viscose Rayon?

  • Cellulose from wood
  • For the pulp industry, wood from a tree with a relatively short harvest cycle is needed.
  • In Indonesia, the type of tree used is mostly acacia.

The harvest cycle of the acacia tree, usually the Mangium or Crassicarpa varieties, is about five years.

  • The other advantage of using the acacia tree is that it can grow well in hilly, mountainous area or low land plateaus.
  • The acacia tree can also improve the structure of the soil where it grows.

 

The Planting Cycle of the Acacia Tree for Industrial Needs.

  • The young leaves and branches are harvested from the mother tree and cut into three-centimeter pieces to plant.
  • Harvesting of the young leaves can be held once a week.
  • The pieces are then planted into planting medium to grow roots.
  • At this stage, they are usually given anti-fungal or pesticidal solution as well as one to speed up growth.
  • The seedlings are kept in a closed and humid area for some eight months until the roots and the tip of the branches grows out.
  • The seedlings are then moved to an open space to acclimatize them for about two weeks.
  • The seedlings are then planted at their permanent location in the open.
  • The harvesting can be done after the trees is more than five years old.

 

Process to Produce Viscose Rayon

  • Alkalization: The making of alkali cellulose slurry while diluting hemi cellulose, or the filling of the space in between the cellulose fibers, using 18 percent NaOh
  • Curing: Using a rotating drum to make the cellulose easier to dilute in the next process, while eliminating alkali metals by passing it through a high-pressure blower
  • Xanthation: The alkali cellulose is then reacted with gaseous or liquid carbon disulfide to produce cellulose xanthate
  • Dissolving and mixing: The cellulose xanthate is reacted with 20g/l of Sodium hydroxide (NaOH) to produce a viscose solution
  • Ripening: Cleaning to eliminate various hindrances such as dust, rust and fine fiber that can clog equipment
  • Wet Spinning: To form rayon filaments or tow
  • Tow Cutting: Using high pressure hot water spray, to produce staple fibers filaments that are cut with length of 32 up until 60 mm. With the water and steam, the extraction of carbon disulfide is also taking place
  • Washing and Soft Finishing: Cleaning remains of coagulant solution and sulfides with a number of wash— acid free wash, first washing, desulfurizing, second washing, bleaching, third washing, final washing— and soft finishing
  • Drying: The fibers are pressed then shredded to produce smaller sized fibres that are easier to dry. Two drying process will leave a water content of about 11 to 13 percent
  • Packing: Fibers are shredded again into staple that are ready for spinning into yarns and packaging
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