by Viscose staple fiber is a type of regenerated cellulosic fiber made from naturally occurring polymers like tree pulp or cotton linters. It is one of the most widely used man-made fibers with about 7 million tons produced globally each year. The manufacturing process involves dissolving cellulose pulp extracted from trees or plants in a strong alkali solution and extruding it through a spinneret into an acidic bath. This causes the dissolved cellulose to coagulate and solidify into filaments. The continuous filament is then cut into short staple lengths which are processed further for use in textiles.
Raw Materials Used
The key raw material used to produce viscose is wood pulp extracted mainly from fast-growing trees like eucalyptus, birch and poplar. About 65-70% of the raw material used is from sustainably managed forests. Cotton linters, which are short Viscose Staple Fiber remains left on cotton seeds after ginning, are also used. Only alpha-cellulose from wood pulp or cotton linters is used for production which ensures minimum environmental impact. The dissolving process converts the raw material cellulose into a highly pure, refined product suitable for spinning into staple fibers.
Manufacturing Process
The manufacturing process involves the following main steps:
– Pre-treatment: Raw material wood pulp is treated to remove lignin and hemicellulose to obtain pure alpha-cellulose.
– Xanthation: The purified cellulose is mixed with carbon disulfide and sodium hydroxide to form cellulose xanthate.
– Dissolution: The cellulose xanthate is dissolved in a sodium hydroxide solution to form a viscose solution.
– Filtration and Deaeration: The viscose solution is filtered and deaerated to remove impurities.
– Spinning: The viscose solution is forced through spinnerets into acidic baths where it regenerates, hardens and forms filaments.
– Washing and Drying: The filaments are washed, bleached, dried and cut into staple fibers of different lengths.
– Drawing and Crimping: The fibers are drawn to increase tensile strength and crimped to provide bulk and resilience.
– Baling: The finished viscose are pressed and wrapped into bales for shipping.
Properties and Uses
Viscose staple fiber has properties similar to cotton but with better strength, absorbency and easy-care features. It is soft, smooth, breatheable and absorbent. Some key properties include:
– High wet and dry tensile strength due to molecular orientation during manufacturing.
– Good absorbency and moisture regain helping the fiber feel soft and comfortable.
– Easy to dye in a wide range of colors without deterioration of properties.
– Thermal properties allowing heat setting without damage.
– Low pilling and fuzz formation during wear and wash cycles.
– Maintains shape and elasticity even after repeated washing and wear.
These properties make viscose suitable for use in various fashion apparel and home textiles. Some major end uses include:
– Woven and knitted garments such as dresses, shirts, pants, lingerie etc.
– Bedding products like sheets, towels, curtains etc.
– Blends in fabrics for shirts, socks, underwear, suits, coats etc.
– Medical textiles for surgical gowns, sanitary pads, bandages etc.
Sustainability and Environmental Impact
One of the main advantages of viscose staple fiber is its ability to be produced from renewable and biodegradable raw materials in a largely closed-loop process. This makes it a more eco-friendly alternative to synthetic fibers:
– Sustainable wood sources and cotton linters are used so there is no dependence on petroleum resources.
– The manufacturing uses fewer chemicals compared to other cellulosic fibers like rayon.
– Recycled and controlled chemicals are used to minimize wastewater effluent.
– Modern production facilities have effluent treatment units to treat and reuse wastewater.
– The fibers are biodegradable and carbon-neutral over time compared to non-biodegradable synthetics.
– It reduces waste by converting agricultural and forestry residues into new textile products.
– Life cycle assessments show viscose has lower non-renewable energy use and greenhouse gas emissions.
Ongoing research aims to further improve sustainability through innovations like biorefinery concepts involving methanol recycling. Overall, viscose offers an eco-friendly fiber choice as the industry moves away from petrochemical-based synthetics.
Industry Outlook and New Developments
The global viscose industry was valued at around $8 billion in 2020 and is projected to grow at a CAGR of 4-5% during 2021-2026. Asia pacific, mainly China, accounts for over 70% of viscose capacity reflecting strong growth in viscose apparel demand. Europe and North America are also major industry driving demand through high viscose blended garments.
To remain competitive against synthetics, viscose producers are focusing on new product developments. Some recent innovations include modal and lyocell type specialty viscose fibers with even better properties. Nanofibrillated cellulose from wood is being used to develop high performance viscose. New spinning technologies allow production of textured and hollow viscose fibers with improved aesthetics and functionality. As sustainability norms strengthen globally, viscose staple fiber is well positioned to expand its industry share in the man-made fiber industry.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it.
